Gemini Industries Printer User Manual

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User’s Manual

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Gemini-10X, Gemini-15X: Star Mfg. Co., Ltd.

Trademark Acknowledgement

grafstar, Universal/Atari Parallel Interface, Universal/Commodore Parallel Interface: Star Micronics, Inc. Apple, Apple II, Apple II + , Apple Ile, Apple Ill, Applesoft: Apple Computer Inc. Atari 400, Atari 800, Atari 850: Atari Inc., a Warner Communications Company Commodore, VIC-20, C-64: Commodore Business Machines, Inc.

CPIM: Digital Research

IBM Personal Computer, IBM PC: International Business Machines Corporation Microsoft BASIC: Microsoft Corporation Osborne 1: Osborne Computer Corporation

TRS80: Radio Shack, a division of Tandy Corporation

0 1994, Star Mfg. Co., Ltd.

Congratulations on having purchased a serial, impact dot matrix printer that offers you more quality, greater flexibility and convenience, and superior reliability than you could find in any other printer in the same price range.

As you already know (or are about to learn), the Gemini-lox and Gemini-15X let you print both regular and italicized alphabets, as well as normal, elite (smaller), condensed, enlarged, emphasized, and double-strike characters. You can print on regular stationery, multiple-sheet forms, fanfold computer paper, or paper fed from a roll (European style).

The graphics capability provided by the Gemini printers is limited only by your graphic talents, and includes three bit-image modes: Low Resolution (60 by 72 dots per square inch), High Resolution (120 by 144) and Ultra High Resolution (240 by 144). With all this printing power at your fingertips, what are you waiting for? Let’s get started!

This User’s Manual is organized to serve both the first-time user and the sophisticated computer buff. The first five chapters provide the basics you need for putting your printer to work in most home and office applications.

Chapters 6 through 10 deliver information for intermediate and advanced users, supported by technically rich appendices. If you are a beginner, you might want to look at Chapters 6-10 sometime in the future, when your curiosity about how the printer does what it does has replaced your initial interest in what it can do.

Take a moment to examine the Table of Contents on the following page. It shows you how this manual is organized to best serve your information needs. You should note, if you are just now unpacking your new printer from its shipment packaging, that Appendix G shows you what you have and how it all fits together. This manual’s first several appendices are computerspecific, and help you connect your new Gemini with your computer. At the back of this manual, there is a glossary that gives simple definitions of common terms. Following the glossary is an index to help you quickly find answers to your questions.

A Quick-Reference Guide is printed on the inside folding flap of the back cover. By reading this manual carefully, and practicing with your Gemini, you should soon be able to achieve full printer performance just by referring to this Quick-Reference Guide.

Congratulations on your purchase of a Gemini. May it work for you long and well.

iii

This User’s Manual serves the operators

of the Gemini-lox and Gemini-15X printers.

The Gemini-lox accommodates paper up to 10 inches wide.

The Gemini-15X can handle paper up to 15.5 inches wide, and can print more characters per line.

Table of Contents

Chapter 1. Chapter 2. Chapter 3. Chapter 4. Chapter 5. Chapter 6. Chapter 7. Chapter 8. Chapter 9. Chapter 10. Appendix A. Appendix B. Appendix C. Appendix D. Appendix E. Appendix F. Appendix G. Appendix H. Appendix I. Appendix J. Appendix K. Appendix L. Appendix M. Appendix N. Appendix 0. Glossary index Consumer Response Reference Guide

Introduction Paper and Ribbon

The Gemini Self-Test

Interfacing Gemini with Your Computer

Putting Gemini to Work for You The Fundamentals of Dot Matrix Printing The Full Range of Printing Capabilities

Downloadable Characters The Function Codes

Maintenance Apple II Plus Atari 8001400

Commodore VIC-20, C-64

IBM-Personal Computer

Osborne TRS80 When You First Get Your Gemini ASCII Code Charts ASCII Code Tables

International Character Sets Character Style Tables Control Circuit Block Diagram

Function Code Summary Gemini’s Parallel Interface Code Chart

1 13 39 47 57 81 99

115 123 143 151 165 179 192

194 206 217 226 230 231 232 241 242 246

254 258 261

INTRODUCTION

Allow us to introduce you to your Gemini printer: “Gemini, this is your new user:’ “User, this is the remarkable new Gemini - a versatile and dependable printer that lets you do tricks with the

a.“.

Ir.

A TOUR AROUND GEMINI

dot matrix and bit image capabilities?

In this chapter, we’ll answer the question: What are the parts of the printer and how do they work together? We’ll define the operating environment for Gemini, and we’ll discuss its technical specifications. If you are just now unpacking your newly acquired Gemini, refer to Appendix G to learn how the pieces fit together, then return to this chapter to discover how to put your printer to work for you.

; e.

Let’s begin with a tour around the outside of the Gemini. On the top, right, front part of your machine, you’ll see the controlpanel (as shown in Figure l-l). These three buttons and the four status lamps are your day-to-day operational controls. These are fully explained later in this chapter, but for now we’ll move on because

this is an express tour.

On the right side of your printer is a large knob and, toward the back, you’ll find the “on/off” power switch. The knob is attached to the platen (pronounced platen), which is the padded roller around which the paper is fed to the printing mechanism.

Hence, the handle is called the platen knob, and allows you to manually turn the platen (with the power “off”), just like on a typewriter.

The power switch, located on the lower right side, is the

“on/off” switch that controls the flow of electricitv to your

machine. The Gemini printers use A.C. power source found

in wall outlets of homes and offices. As a safety precaution, you should make sure that your printer is turned “off” before plugging the three-pronged safety plug into the electrical outlet.

Turning the corner and examining the back of your machine

(as shown in Figure l-2), you’ll see the power cord, grounding

connector, interface ports, and DIP switches.

The DIPswitches (a popular acronym for the electronic term, “dual in-line package”) control important printer functions. Some companies call these “microswitches” because their engineers made them so small you almost need a microscope to find and

Gemini User’s Manual

set them. Other products call them “internal switches” because you must take their printers apart to get to them. The Gemini DIP switches are easy to set, which is explained in Chapter 4.

Next to the DIP switches is the connector for the parallel

interface. This is where you connect your Gemini to your personal

computer, so they are “interfacing:’ and able to communicate with each other. (Appendices A through F provide information on hooking-up your Gemini with six widely used types of microcomputers.) This connector is for a “parallel” interface, a type of interfacing that is accomplished by having the printer “parallel-wired” like a string of double-wired Christmas lights, where each lightbulb burns independently. Data from your computer is sent down the cable wires to your Gemini side-by-side, or “parallel?

Between the parallel interface and the power cord is the “port hole” (a punch-out plastic tab) for the serialinterface. This optional interface allows you to connect Gemini with a computer requiring serial communications.

figure 1-1. The operational controls are on the right side of the Gemini printers.

Introduction

Grbund terminal

DIP switches

Connector for parallel Interface

“Port hole” for serial Interface (optlonal)

-3%

Figure 1-2. back of the Gemini printers.

A SNEAK PREVIEW INSIDE GEMINI

The connectors and DIP switches are located on the

By referring to Figure 1-3 we can examine more closely the parts

that make your Gemini printer work.

If you are just getting started, you should refer to Appendix G for instructions on unpacking and assembly, then to Chapter 2 for information on loading the ribbon and setting the print head’s gap. After you’ve cleared those hurdles (which you’ll do soon enough), this is what your printer will look like.

Inside the front of the machine are two ribbon spoo/s. Gemini

uses standard typewriter ribbons, saving you money you might have had to spend for special-purpose ribbon cartridges. When the ribbon has run completely from one spool onto the other, the Gemini automatically reverses the ribbon direction. When the ribbon starts wearing (and the print copy lightens), simply take the ribbon off, turn it upside down, and print on the other edge.

The cylindrical print head (observable behind and above the

ribbon spools) is the ingenious device that can print 120 characters per second (CPS) onto a variety of papers. What’s more, the print head is engineered to work consistently for an average of 100 million characters without fail (expressed as 10 x 10’ Mean

Gemini User’s Manual

Paper separator

Paper gulde

Figure 1-3. For more information about how the paper guide, separator, and holder should be attached to the printer, please refer to Appendix G at the back of this manual.

Curve Between Failures). If you ever need to replace the print head, you can detach it yourself for replacement.

The Gemini prints by means of pins that are thrust from the “working” side of the print head. These pins impact against the paper, which is backed by the platen. As already mentioned, the platen is like the roller on a typewriter. The individual characters

(letters, numerals, and symbols) that are printed result from the action of the dot-producing pins. These wiry little pins “fire” dots

Introduction

onto the paper, with the dots arranged according to preset matrix

patterns (imaginary grids). Because the characters are printed in a series (one after the other), Gemini is called a serial, impact dot

matrix printer.

propelling fanfold computer paper. The tractor unit is used with computer paper having perforated and punched paper guides on the sides.

0 POWER 0 READY DON LINE

0 PAPER

OUT

Above and behind the platen is a device for bearing and

The “power” lamp glows green when the power is “on:’ The “ready” lamp gives you the green light for “go” when the

printer is ready to accept data. During transmission, the lamp flickers.

The “on line” lamp is green, and glows when data transmission

is possible.

The red lamp of “paper out” means just that: your printer is out of paper and has stopped printing.

The “On Line” button lets you alter the printer status between be-

ing “local” (which means independent and on its own) and being “on line” (which means able to receive data transmitted from a

computer). When you turn the printer’s power “on:’ you’re

automatically “on line!’

F.F.

figure 14.

F.F. stands for “Form Feed:’ When you’re in the “local” mode, you can tap this button and advance the paper that is being “fed” into the printer to the first line of the next page, or to the start of the next form.

L.F. means “Line Feed” and allows you to advance the paper one line at a time. It’s like rolling a page through a typewriter, advancing you to the next line. If you hold this button down, you’ll get consecutive line feeds, one right after the other.

-1

The control panel (atop the right front of your prin tetj tells you the status of your controls, lets you switch between “on line” and “‘local,” as well as feed more paper through your machine. Take Gemini “off line”(so the “On line” lamp goes off) to operate the form feed and the line feed.

Gem/d User’s Manual

TME CONTROL PANEL

Let’s turn our attention to the buttons and status lamps on the

control panel. Figure l-4 shows what the buttons and lamps can do for you.

The two buttons in front are used to advance paper through the printer, to the next line on which you want to print. L-Fadvances the paper one line at a time, and F.F. moves the entire form (or page) forward.

The Online button allows you to switch between being “online” (meaning hooked-up and in a data transfer mode) with your computer, and being “local:’ Local means that the printer is incommunicado - not in a communicating mode with your computer.

A PRIMER OF YOUR PRINTER’S BASIC COMPONENTS

This section is provided for those of you who are new to computer printer technology, and for now only want to know the most basic

information about how the Gemini works.

Figure l-5 shows what is called an “exploded” view of

Gemini-lox’s major components, and Figure 1-6 is an elementary

logic block diagram for both models. But, because the Gemini printers are so well designed, it isn’t necessary to know detailed information about how it works - just that it does.

Expressed simply, when you turn the power switch “on:’ the

alternating current is converted into direct current for the power

unit. The direct current powers the motors and the print head, as

well as providing power to the control board. The control board does just that: controls the printer by means of a maze of transistors, resistors, diodes, capacitors, and integratedcircuits

(IC, for short).

The control board contains the ROMs and RAMS, as

explained in the Glossary at the back of this manual. For now, it

is enough to know that the control board is the “brains” of the

machine. In fact, your new printer is smart enough to realize when

it has finished printing a short line, and instead of the print head

making an unnecessary trip along the rest of the blank line, Gemini moves the paper up automatically, so no time is wasted before the

next characters are printed. This is why Gemini is said to be logic-

seeking.

- -

Introduction

Connector for oarallel interface

board

Optional serial interface

(punch-out tab)

unit

Lower casing

- .

Power switch

Figure l-5. The main components of the Gemini printer are the power unit, the control board unit, and the printer mechanism (which features a

detachable tractor).

The control board also contains the buffer that allows your computer to send a batch of information to be printed, which Gemini then stores until it can get to it. Although Gemini is a fast

Gemini User’s Manual

printer, computers communicate data even faster. The buffer can accommodate 816 characters of memory, with an optional buffer that can be expanded to 4K or 8K. Qu’est-ce que “K”?

Computer memory is measured in terms of K, meaning ki/o&fes. A kilobyte is 1,024 bytes, and a byfe equals one letter of the alphabet (or a symbol, or a number).

The print-out is accomplished by theprintermechanism, also shown in Figure l-5 and represented in Figure 1-6. The printer

mechanism can produce a variety of typographical styles and sizes (including superscripts and adjustable tabs, and block graphics. Plus, the Gemini is outstanding for the full range of papers upon which it can print.

subscripts), variable line spacing,

I -

Figure 143. This block diagram presents, in simple terms, the relationship among the transformer, power supply, printer mechanism, and circuit control.

For more information on the control circuit, please refer to Appendix L.

_--------

CONTROL LOGIC

BOARD UNIT

1 I

A.C. Power

I I

introduction

GEMINI’S OPERATING ENVIRONMENT

When you install your Gemini printer, you should use common

sense and good judgment about where you place it. The following are worthy of consideration in evaluating a potential operating environment:

Position Gemini horizontally on a level surface.

Pick a place that does not have

extremes in temperature

(very hot or very cold) strong vibrations dusty atmosphere oil present metal particles nearby.

Avoid placing Gemini where it will be exposed to direct sunlight, or close to a heater or heatgenerating applicances.

Provide a separate power supply, away from

noise-generating motors. The power supply must not be more than 10%

more or less than 120 volts A.C., 220 volts A.C., or 240 volts A.C. (as specified on the product identification plate). Note: Extremely high or low voltage will cause printer printer problems.

The Gemini printers are valuable information-handling tools. These tips will help you pick a good setting for the Gemini. Chapter

10 provides maintenance suggestions for keeping your printer in

good working order.

TECHNICAL SPECIFICATIONS

The following table provides a summary of the technical specs for the Gemini-lox and the Gemini-15X. If you understand all of it,

great! If you don’t, that’s okay, too. Either way, by the time you finish reading this manual, you should know more than enough to use your printer to its full potential.

Note: The technical specifications of the Gemini printers are subject to change without notice.

Gemini User’s Manual

Printer: Print head: Print speed:

Print buffer: Character matrix:

Character sets:

Character fonts:

Special features:

Serial impact dot matrix 9 wire (user replaceable) 120 CPS (at 10 CPI) bidirectional logic seeking. Graphics mode: unidirectional 816 bytes (expandable up to 4K or 8K)

9 x 9 standard with true descenders

18 x 9 emphasized

18 x 18 double strike 6 x 6 block graphics 60 x 72 low-resolution bit-image graphics

120 x 144 high-resolution bit-image graphics 240 x 144 ultra-high-resolution bit-image graphics

96 standard ASCII characters 96 italic characters 64 special characters 32 block graphic characters 96 Downloadable characters (programmable) 88 International characters (selectable)

Normal (10 CPI)

Elite (12 CPI)

Condensed (17 CPI)

Emphasized

Double strike

Enlarged (5, 6, 8.5 CPI)

Super/subscripts

Italic

Self-Test

Continuous underline

Backspace

Vertical, horizontal programmable tabs

Left and right margin set

7 or 8-bit selectable interface

Bit image column scan

Perforation skip

Downloadable characters (programmable)

Macro instruction

‘rl -

introduction

Mean curve between failure (MCBF):

Print head MCBF: Columns (maximum):

Line spacing:

Paper slew:

Paper handling:

Interface:

5 x lo8 lines (excluding print head)

10 x 10’ characters

GEMINI-10X GEMINI-15X Normal 80 136 Elite Condensed 136 Enlarged 40, 48,68 68,82,116

l/6, l/8, 7/72 plus programmable by n/72 or n/144 inches

10 lines/second (at l/s-inch spacing)

Fanfolded

Roll paper

Single

*Note: fanfold = 1 original & 2 carbonless copies

Standard parallel (Centronics compatible) Serial RS-232C (optional)

GEMINI-10X width = 3-10 inches copies 3 sheets’ thickness =

0.07-0.1 mm (1 part)

0.28 (3 parts)

width = 8.5 inches thick = 0.07-0.1 mm diameter of roll =

5 inches maximum width = 8-10 inches thick = 0.07-0.1 mm

163 233

GEMINI-15X width = copies 3 sheets” thickness =

width = thick = 0.07-0.1 mm

diameter of roll =

width =

thick = 0.07-0.1 mm

5-15.5 inches

0.07-0.1 mm (1 part)

0.28 (3 parts)

8.5 inches

5 inches maximum

8-15 inches

I/F protocol:

Ribbon:

Dimensions:

Weight:

Power:

Parallel by BUSY, ACK

Serial by BUSY, XONIXOFF’, ACK’

‘When used in conjunction with the STAR Gemini 10X/15X

buffered interface.

Standard Underwood spool-type, 13 x 50 mm

GEMINI-10X

Width

Depth

Height

pounds kilograms 7

120 VAC f lo%, 60 Hz., approx. 1A

220 VAC f lo%, 50/66 Hz., approx. 1oOW 240 VAC f lo%, 5J/60 Hx., approx. 1OOVV

15.2 inches 392 mm

12.4 inches

315 mm

5.8 inches 148 mm

GEMINI-10X GEMINI-15X

15.4

GEMINI-15X

21.3 inches 542 mm

12.4 inches 315 mm

5.8 inches 148 mm

22 10

PAPER AND RIBBON

With Chapter 1 now “imprinted” in your memory, you’re almost

ready to apply all these new discoveries about the Gemini printer. In this chapter, we’ll learn how to load paper into the printer, install the ribbon, and set the print head gap. Chapter 3 will give you a chance to print something; to see the results of what you’ve

learned so far. But first, let’s explore the options for loading

different types of paper.

If you’ve borrowed a Gemini printer (until getting your own),

you should refer to Appendix G to learn how to attach the various

paper-feed accessories. Appendix G tells you what the new owner gets when first opening the box and how all the pieces fit together.

This chapter assumes you know “how” the pieces fit together, and

you only need to learn “why:’

LOADING THE PAPER: INDIVIDUAL SHEETS

The Gemini printers are designed to accommodate individual sheets -

memorandum, multilayer carbonless business forms, an envelope,

or almost any other single sheet.

The Gemini printers can handle individual sheets of paper

according to the following parameters.

whether it’s standard-size stationery, an off-size

Prlnter

Gemini-lox Gemlnb15X

SlngbShret Size Speclflcatlons

Paper Wldth

Minimum Maximum

8 inches 8 Inches

10 inches 15 Inches

Paper Thickness

Mlmimum Maximum

0.07 mm

0.10 mm

Removing the Tractor Unit

The tractor unit is only used with fanfolded computer paper. (That’s the paper that comes in perforated sheets, folded into stacks, with rows of holes along the right and left edges.) To

print onto single sheets, you need to remove the tractor unit.

To remove the tractor unit, follow these simple steps:

Turn off the printer. (This isn’t really a

“requirement:’ but is a good safety precaution, at least until you become more experienced with your Gemini.)

Gemini User’s Manual

Identify the two “snap levers” by comparing your printer with the Gemini-lox shown in Figure 2-1.

Pull both “snap levers” forward (one on the right and one on the left of the tractor unit), and at the same time. . .

. . .

Rock the tractor unit up and back, about a half-inch. The tractor unit rests on two “stoppers” just above the right and left ends of the platen. This step in removing the tractor is done by simply rocking the unit backward after you’ve released the snap levers that hold it in place.

Now lift the tractor unit toward you, up and forward from the printer.

Superman may be able to stop a speeding locomotive, but you just lifted a tractor! With the tractor removed, your Gemini should look like the printer shown in Figure 2-2. (Of course, if you have a Gemini-15X your printer will be wider, but you still get the idea.)

Paper and Ribbon

FigureZ-1.

The Gemini tractor unit is easy to remove for using single

sheets or roll paper.

Tractor frame -

Release lever

Figure 2-2.

Tractor frames support the unit on the left and the right. Be

sure to adjust the release lever when removing or mounting the tractor unit.

Gem/n/ User’s Manual

Note:After removing the tractor unit you’ll need to set the “release lever” when you are ready to print single sheets. The release lever is located on the left side of the printer (see Figure 2-2). This is somewhat like shifting an off-road vehicle from two-wheel to fourwheel drive. On the Gemini printers, you need to “shift” the release lever forward so it aligns with the ‘7” for “tractor” when the tractor unit is in use. But with the tractor unit removed, you need to shift the release lever backward so it aligns with the ‘IF!’ (The “F” stands for “Friction feed:’ which is the “drive” setting for single-sheet and roll-fed paper.)

Inserting Single-Sheet Paper

Turn the power “off:’

Make sure the release lever (on the left

side of the printer) is set in the “T”

position (which is the “open” mode for inserting the paper; you’ll “close” it to

the “F” mode in a moment).

Lift up the paper press, as shown in

Figure 2-3. (This step is the same as if you were inserting a sheet of paper into a typewriter.)

Insert the sheet of paper from the back side of the platen, between the paper chute and the platen cover. Push the

paper through to the upper front side of the platen.

Adjust the paper horizontally (right and

left) so the sheet is where you want it.

Be sure the area you’re going to print on the sheet is within the margins you’re going to set for the printout.

Make sure the paper is in straight.

.‘:

: “.

Paper and Ribbon

.Position the sheet of paper where you

want the first line of text to start printing. (It may take you a little practice

to get the placement consistently right,

but you’ll master it quickly.)

Push the release lever back to the “closed” position, indicated by “F1’

Return the paper press to the original position, flush against the paper.

10.

Replace the cover and turn the power “on?

Note: Never touch the printing head during printing. Aside from the mechanical injury threat associated with touching a fastmoving device, there is the danger of burning your fingers. As

the caution label on the print head states:

Caution: Hot Surface, Avoid Contact

Release lever

Paper

I -KC$Bk

Single sheet paper

, Paper chute

Figure 2-3.

Inserting a single sheet of paper into the Gemini-15X (shown here) and the Gemini-lOXis just as easy as rolling a sheet ofpaper into a standard typewriter.

LOADING ROLL PAPER

The Gemini printers also allow you to print from rolls of paper. The specifications are the same for both the Gemini-lox and the Gemini-15X.

,.:

2: .:

. . . . .’

. .

: : . .

..)

‘:jY y

:..

> ” ‘. ‘.

.: ,, :

::: .,

Roll paper width:

Roll paper thickness: 0.07-0.10 mm

Diameter of roll: 5 Inches (maximum)

Roll paper, like single sheets, is fed into the printer by what is

called “friction feed? Thus, the use of roll paper requires

removal of the tractor unit.

Gemini User’s Manuai

8.5 inches

Paper separator

Figure 2-4.

Both Gemini printers use similar paper guides and

separators and iden tical roll-paper assemblies.

Paper and Ribbon

Roll paper utilizes the metal racks, which come as accessories with every Gemini printer. As shown in Figure 2-4, these accessories include the paper guide, paper separator,

roll-paper holder, and holder shaft. For information on how to attach these accessories, please refer to Appendix G.

The steps for inserting roll paper are fairly simple and

straightforward:

1. Turn the power “off:’

Remove the tractor unit, if you haven’t already done so.

Following the procedures described in Appendix G,

attach the paper

separator, guide, and holder.

Pull the release lever (located on the left side of the top-front part of the printer) into the “open” position. As with singlesheet paper, the “open” position is indicated by the letter “TV

Lift the paper press.

6. Pull the paper separator upright, as depicted in Figure 2-4 (for the Gemini-lox). The paper guide should remain horizontal.

Load the paper roll, as shown in Figure 2-4, so that when viewed from the printer’s right side, the paper will unroll in a clockwise direction.

8. As shown in Figure 2-5 (for the Gemini-15X), unroll some paper and pass it above the paper guide and underneath the up-ended paper separator.

paper separator

Gemini User’s Manual

guide

Figure 2-5.

inserting roll paper in the Gemini printer is similar to inserting sing/e sheets, with accessories to accommodate the fact that the “sing/e-sheet” in this case is quite long.

Insert the roll paper into the paper chute, then push the paper through so

it goes around the platen.

When the paper has been pushed

10. through so it’s above the paper press,

push the press back so it’s in its operational position (that is, flush against the paper).

Adjust the paper, if necessary, so it will

11. feed through straight; then push the

release lever back to the “locked” or “closed” position, marked with the letter “FI’

12.

Lower the paper separator, as shown in Figure 2-6.

Paper and Ribbon

13. Rotate the platen knob and check to see if the roll paper is feeding smoothly. If some adjustment is needed, pull the

release lever forward to the “open” mode again, and adjust the placement

of the paper before “closing” the release lever.

14.

Set the print-start position to where you want to begin printing on the roll.

15.

Turn the power switch to the “on”

position.

Figure 2-6.

After the roll paper has been inserted and the various mechanisms set in their proper places (steps 70- 12), you can turn the platen knob to adjust the roll paper vertically.

Note: If you encounter any problem finding suitable roll-paper

supplies, contact your Gemini dealer.

LOADING SPROCKET-FED PAPER

Sprocket paper is also known as “computer paper:’ fanfold paper, and “perf” paper (for “perforated”). Even if you call it “That funnylooking paper with rows of holes on the sides:’ your Gemini can still print on it.

Sprocket Paper Speclflcations

Parameter

Gemini-lox Gemini-15X

Gemini User’s Manual

copy:

minimum maxlmum

Paper width:

minimum maximum

Paper thickness:

Single sheets

minimum maximum

3-part forms*

*Gemini can print 3-part “carbonless” forms, which consist

of one “original” sheet and two “copies.”

Mounting the Tractor Unit

Figures 2-1 and 2-2 showed you how to remove the tractor unit from

your Gemini. The tractor unit drives (“feeds”) the sprocket paper through the printer. When you want to print onto this type of paper, you must first attach the tractor unit. Figure 2-7 shows you the

correct alignment for gliding the unit into position and snapping

it into place.

The tractor units for the Gemini-lox and Gemini-15X are quite

similar, but the paper-loading procedures are markedly different. So the following sections instruct you on loading sprocket-fed

paper into each type of printer. But first, let’s look at the tractor

unit and its main parts.

1 sheet

3-part form’

3 inches

10 inches

0.07 mm

0.10 mm

0.28 mm

1 sheet

3-part form’

5 inches

15.5 inches

0.07 mm

O.lOmm

0.28 mm

Paper and Ribbon

Left sprocket mechanlrm

Right sprocket mechanism

j L

Figure 2-7.

Mounting the tractor unit is a “glide and snap.” Glide the unit

down until the A’s align, then snap the unit down so the B’s lock into place.

Facing your Gemini, as depicted in Figure 2-7, you see the tractor’s driving gear-wheel that is on the right (protected by a “fender:’ complete with a “fender skirt”). To the left of this part is the right sprocket. On the other side of the spacer(s) is the left sprocket unit. These mechanisms drive the paper through the printer. Each has a hood, secured with a spring. Try lifting the hood, if you want.

Toward the back of the top of each sprocket mechanism is a clamp lever. If you snap the lever forward, you can freely move the sprocket mechanisms back and forth to handle different widths of paper. When you have the mechanisms where you want them, snap the clamp lever backward, and it acts like a parking brake.

Gemini-lox Loading Sprocket Paper

The Gemini-lox should be loaded with sprocket-fed paper

according to the following steps.

Turn the power switch “off?

Gem/n/ User’s Manual

10.

Install the tractor unit.

Install the paper separator and paper guide, as described in Appendix G.

Pull the release lever, located on the left side of the printer, toward the “open” position (marked ‘IT”).

Lift up the paper press.

Pull the paper separator upright, as shown in Figure 2-8.

Place the stack of fanfolded computer paper behind the printer.

Pick up the top sheet of paper and feed it

between the paper chute and the platen cover, from the back side of the platen.

Push the paper down and forward, so it wraps around the platen.

Return the paper separator to its original

position,

11.

Open the tractor covers atop the right- and

left-sprocket mechanisms, as shown in Figure 2-9.

Pull the paper up, past the sprocket

12. mechanisms.

Paper and Ribbon

Figure 243.

Feed the paper around the p/a ten (“roller’l) of the Gemini- 10X,

then push the paper separator “downrightY(That’s the opposite of “upright”

not to be confused with “downwrongl’)

13.

Flip the clamp levers forward on the sprocket mechanisms; adjust each mechanism (right and left) so that the sprockets (the nubby little “teeth” protruding from the sprocket wheel) align with the holes on the paper.

14.

Adjust the sprockets so they are lined up with the sprocket holes.

15.

Close the tractor covers and snap the clamp levers back into the “locked” position. (See Figure 2-10.)

16.

Rotate the platen knob, and roll the paper up or down until the correct “print-start” position is obtained.

17.

When the paper installation is completed, replace the printer cover and turn the power on.

Tractor cover

Gemini User’s Manual

Clamp lever

Figure 2-9.

Expose the “teeth” of the sprockets, and align the

mechanisms so the paper “feeds” through them.

Figure 2- 70.

If the sprocket paper you just loaded in your Gemini-lox is multilayer (non-carbon) forms, then refer to the end of this chapter to learn how to adjust the print-gap.

Paper and Ribbon

Gemini-l 5X Loading Sprocket Paper

The Gemini-15X can be loaded with sprocket paper exactly the

same as can the Gemini-lox, but with one important difference. The Gemini-15X is designed to accept paper either from the back of the printer or paper fed from beneath the printer. That’s right, there’s a slot in the undercarriage that lets you position the

Gemini-15X above your stack of fanfold computer paper; this paper is fed up through the printer and out the back.

Following are the steps for loading sprocket paper to and

through the Gemini-15X. Figure 2-11 illustrates steps 1 through 6.

Turn the power “off?

Install the tractor unit, as illustrated in Figure 2-7 (on page 23).

Attach the paper separator and paper

guide (they are the two metal racks that are described in Appendix G).

Pull the release lever, located on the left side of the printer, toward the “open” position (marked “T”).

Raise the paper press.

Lift up the paper separator.

Raise the tractor covers on the sprocket mechanisms (as shown in Figure 2-12).

Snap the clamp levers (atop the sprocket

mechanisms) forward to the open position,

and move the sprocket mechanisms away

from each other until there is enough room between them to accommodate the paper.

Paper separator,

Gemini User’s Manual

Figure 2-l 1.

The first step is to prepare the Gemini-75X by putting the

mechanical controls in the “open”position.

Stepsg-12leadyoudown twoseparatepaths:Steps9A through

12A are for loading sprocket paper from “behind” the printer; steps 9B through 12B instruct you on loading paper from “beneath” the Gemini-15X.

9A.

Place the stack of fanfolded computer paper behind the printer.

10A. Insert the sprocket paper from the back of

the printer (as shown in Figure 2-12).

11A. Feed the top sheet between the paper

chute and the platen cover, and around the platen to the front.

12A. Push the paper up past the paper press,

and return the paper separator to its horizontal position.

Paper and Ribbon

The other option is to:

98.

1OB. Pick up the first sheet of the perforated

11B. Push the paper up toward the front of the

12B. Feed the top sheet inside the paper press

Place the sprocket paper below the printer (ideally, on the second shelf of a specialpurpose printer table, with the printer above it on a shelf with a built-in slot).

stack of fanfolded pages, and lift it up and through the slot in the undercarriage of the Gemini-15X.

platen.

and past the platen, far enough up so you can grip the paper from above the printer.

Figure 2- 12.

The Gemini-15X can be loaded with sprocket paper from the back (as shown here) or from a stack of paper beneath the printer (depicted in Figure Z-13).

Gem/n/ User’s Manual

“Back Pass”

Figure 2-13.

“Bottom Pass” : . .

loadlng :

Whether you use the “bottom pass” (shown here) or the

“back pass” option (also shown), you start and end with the same steps.

13. Adjust the paper so that it will feed through straight, and push the paper press back to its operational position.

14.

Horizontally adjust the sprocket mechanisms right or left so they align with

the sprocket holes on the paper.

15.

Vertically turn the sprocket “teeth” (the

little nubs on the sprocket wheels) so they line up with the holes on the paper.

16. Snap the clamp levers back into the “closed” position.

Paper and Ribbon

17. Close the tractor covers.

start position of the paper.

19. Turn the power “on” and put your Gemini to work for you.

NoWThe best “start-position” (step 18) will vary according to the paper on which you are printing and the number of blank lines in your document. If you are a novice with dot matrix printers, you might try to position your paper just above the in-place paper press for your first attempts. With practice, you’ll be able to place the paper right where you want to start printing.

18. Rotate the platen knob, and set the print-

Another note: If you use multipart paper (such as a three-sheet

carbonless form) with your Gemini-15X, you’ll need to adjust the print gap, as discussed later in this chapter.

Congratulations! You’ve learned how to load the paper.

Next, we’ll discuss the ribbon and print gap,

then you’ll be on your way to less reading and more printing.

LOADING THE RIBBON

You already know that your Gemini printer is one of the best buys

available today in terms of what you get for your initial investment. What’s more, Gemini’s sensible ribbon requirements are even more economical as time passes.

That’s because Gemini uses ordinary typewriter ribbons on spools. When the ribbon has gone from one spool to the other, Gemini automatically reverses the ribbon direction.

After the ribbon starts wearing out (when your printed material starts getting too light), you can invert the ribbon and start over.

Replacing the ribbon (which you’ll have to do eventually) is easy and inexpensive.

Geminl User’s Manual

Ink Ribbon Speclficatlons

Ribbon Color Material Dimensions

width:

length:

Spool Standard

Recommended Product

black nylon (#40)

112 inch (13 mm)

11.5 yards (10.5 m) Underwood’s plastic type

(13 x 50 mm diameter) Type SF-OSB made by

Fuji Kagakushi Kogyo

Near each end of the ribbon, there is a metal or plastic eyelet that signals Gemini to reverse the ribbon direction. It will do this automatically. When loading the ribbon, you should be careful to place the eyelet properly in the ribbon’s threading configuration.

Paper and Rlbbon

How to Set the Ribbon

Telling you how to set the ribbon is like writing a narrative

describing how to tie your shoelaces. Figure 2-14 and 2-15 show you the way to thread the ribbon on the Gemini-lox and

Gemini-15X, respectively. But before you try it, you would do well to review the hints provided here.

Hint PI:

Hint #2:

Figure 2-14.

Turn the power “off:’

Slide the print head gently with your fingers to the approximate center of its pathway (Figures 2-14 and 2-15).

The ink ribbon pass for the Gemini-lox.

p _.-.__-.-. -.--77

Ribbon guide

.-._

r/ Ribbon guide

.-.-._.

-.-.-.- .-._._. ~

b&Yp.a-

Figure 2- 15.

The ink ribbon pass for the Gemini-75X.

Ribbon spool

Gemini User’s Manual

Hint #3:

Begin by setting either ribbon spool securely on a ribbon spool axle. Make sure you have the spool positioned so it will wind/unwind as shown in the figures. Place the spool securely on the axle, so that the “drive pins” engage the spool.

Figure 2-16.

You might want to use a ball point pen to lightly press

the ribbon guide toward the platen while inserting the ribbon.

Hint ++4:

Then thread the ribbon, taking care around the print head. Figure 2-16 shows how to

insert the ribbon in the slot between the

print head and the ribbon guide. Figure 2-17 shows you how to position the ribbon to avoid misprints or to prevent the ribbon coming off during printing.

Paper and Ribbon

ink ribbon

(incorrect)

Figure 2- 17.

Print head

(incorrect)

Two wrongs don’t make a right, so try to be careful

Ribbon guide

(Correct)

when setting the ribbon near the print head (shown here).

Release lever

Eyelet grommet

Ribbon spool

Figure 2- 18.

The eyelet grommet (which signals Gemini to

automatically reverse the ribbon direction) is shown correctly placed on

the ribbon-spool side of the changeover lever.

Gemini User’s Manual

Hint #5:

The eyelet grommet (which signals Gemini to automatically reverse the ribbon direction) should be placed on the ribbon-

Hint #6:

spool side of the changeover lever.

Set the other ribbon spool on the opposite

spool axle, making sure the “drive pins” are

Hint #7:

engaged.

When the ribbon threading has been

accomplished, turn the ink ribbon spools by hand, approximately four or five rotations of the spools. This verifies that everything was done properly and that the ribbon is smoothly fed.

Hint #8:

As shown in Figure 2-19, you can turn the ribbon over and use the other side when it starts wearing out.

Used up

Figure 2-19.

Turning the ribbon over gives you the same effect as

having a new ribbon but at no extra cost.

Paper and Ribbon

ADJUSTING THE GAP BETWEEN THE PRINT HEAD AND PLATEN

Gemini printers can accommodate papers of varying thicknesses

by allowing you to change the print-head gap. This “gap” is the distance between the print head and the platen.

Gap adjustment is done by moving the “adjust lever:’ which is immediately in front of the “release lever” (see Figure 2-18). Pulling the “adjust lever” forward will widen the gap, and pushing it backward will make the print-head gap narrower.

There are five positions that can be attained by moving the lever to different adjustments. These five positions can be changed by the control arm rest in different notches, as shown in Figure 2-20. The “second position” is most commonly used for single sheets of paper.

Figure Z-20. /ever allow you to print on paper ranging from 0.07 mm (that’s thin) to

0.28 mm (for three-layer carbonless forms).

The different positions of the print-head gap-adjustment

If you are unsure of which is exactly the right print-head gap adjustment to make, experiment. In time, you’ll get the best results.

With the turn of a page, you’ll be ready to check your work,

as Chapter 3 introduces you to Gemini’s Self-Test.

_& - -M-u,“‘=

._s. M.

- --------

L..

II.

GEMINI SELF=TEST

“Self-Test” is the name of the built-in program that prints out several sample lines of letters, numbers, and other characters to show you that everything is in good working order. You can print the Self-Test without hooking up your Gemini to a computer.

The Gemini Self-Test is a special feature that allows you to check your installation of the paper and ribbon and the adjustment of the print head gap. At the same time, the printout provides a preview of what’s to come: all the standard characters in both normal and italic type styles.

HOW TO INITIATE THE SELF-TEST

The Gemini Self-Test is as easy as “one, two, three?

3. While holding down the “LF” button on the

The Self-Test (shown on the following two pages) will print out

automatically. If you hold down the “LF” button, the Self-Test will continue printing out.

The Gemini-lox Self-Test (Figure 3-1, a &. b) consists of four lines that show the standard character set that your printer can produce. The Gemini-15X Self-Test (Figure 3-2, a & b) uses the

same characters, and is also displayed on four lines.

Chapter 4 if you are in a hurry to hook-up your Gemini to your

computer and start printing out data that you generated. On the other hand, if you want to take a few minutes to finish this chapter,

you’ll learn what these characters represent and how to use them.

Plug the printer’s electrical plug into an

1. electrical outlet.

2. Insert a sheet of paper.

control panel, turn the power switch “on?

After you run the Self-Test on your printer, you can skip to

WHAT THE SELF-TEST LOOKS LIKE

Gemini User’s Manual

I I

Figure 3-la. actual size).

The left side of the Gemini-lox Self-Test printout (shown

Figure 3-2a.

actual size).

The left side of the Gemini-15X Self-Test printout (shown

Self- Test

I I

GHIJ~::LMNOF’QHSTlJVWXY%C\l.“‘_ ‘abc:defghi _il:lmno , 0

I I

Figure 3- 1 b.

The right side of the Gemini-lox Self-Test, which is a

continuation of this two-part figure.

Figure 32b.

The right side of the Gemini-15X Self-Test, which is a

continuation of this two-part figure.

Gemini User’s Manual

WHAT THE SELF-TEST MEANS

The Gemini Self-Test allows you to test the printer’s performance

before putting it to work. Beyond that, the Self-Test is a demonstration of some of the characters Gemini has stored in

its permanent memory.

On the following pages, groups of characters from the Self-

Test are identified and discussed. Where a character has multiple

meanings or uses, this manual provides the most common and

generally used.

In discussing these characters, we face the old problem of

defining a word without using that word in the definition. To make

it easier to identify which character we’re discussing, we’ve coded some of the characters to correspond with letters of the English alphabet. If you look at Figure 3-3, you’ll see that the fifth character shown in the sequence on the lower line is the “percent” sign. For

purposes of our discussion, we’ve coded it so it corresponds to the letter “f” above it. In Chapter Five, you’ll learn about other

“codes” that have been created to facilitate discussion about computer-generated characters.

abcdefghijklmnop

,T!

rstuvwx

!“#B%&’ Ot+,-./012345678Y:~(->?B

Figure 3-3.

The first part (of the first Self-Test lines) shows the

characters often associated with the top row of keys on a typewriter.

- -

Se/f-Test

In Figure 3-3, the letter “a” codes a character that’s as hard to see as the wind. That’s because the first line begins with a blank space.

The “blank” character may not seem important, but without

it:

everythingwouldruntogetherlikethis

The first character that appears in the lower line of Figure 3-3

is the “exclamation point” (coded “b”). This is also called the “factorial” sign in mathematical symbolism.

The next eight characters (represented by “c” through “j”) are,

respectively: double quotation marks, the “number” sign (if it precedes a numeral: as in #!5; or a “pound” sign if it follows: as

in W), the dollar sign, the percent sign, the ampersand (also called the “and” sign), the apostrophe (which also serves as the “final single quotation mark), and the opening and closing parentheses.

The next six characters in Figure 3-3 (represented by letters

“k” through “pi’ respectively) are: the asterisk(or star), the “plus” sign, a comma, the “minus” sign (which also serves as both the

hyphen and the short dash), a period, and the “slash” mark. The

“slash” (represented by letter “p” is also called the “diagonal:’

“slant:’ “solidus:’ and “virgule”; in the English money system, it

represents “shillings?

Letter “q” in Figure 3-3 represents the 10 characters for the numerals “zero” through “nine:’ It might help to note the difference between a “number” and a “numeral” at this time. A “byte” can represent a character (such as the letter “m” or the numeral ‘?I”), or a whole number. A “number” is a concept, and a “numeral” is a character or group of characters that represent the concept.

In Figure 3-3, the letters “r” and “s” stand for the “colon” and “semicolon” characters. The next three symbols are mathematical signs that show the relationships of values. “cl’ means “is less than”(such as “3~4”); “=I’ is the “equals” sign (and the “doublebond” sign in chemistry); and I‘>” means “is greater than” (such as “6>4”). Next comes the “question” mark, and finally the “at” sign. In everyday usage, “@” may be used like this: “4 diskettes @ $5 = $20.” In some software packages, such as VisiCalc, the “at” sign is part of a powerful command sequence.

Figure 3-4 presents the second part of the first line in the Gemini Self-Test. The first 26 characters are the English alphabet’s capital letters. These are also called the “upper case” letters.

Gemini User’s Manual

a bcdef

ARCDEFGHIJKLMNGPQRSTlJVWXYZC\l’.~-’

Figure 3-4.

The Self-Test prints the uppercase alphabet in the first

line, 10 characters per inch. In Chapter 5, you’ll learn how to print larger

and smaller letters (from 5 to 17 characters per inch).

In Figure 3-4, the characters coded “a” and “c” are “brackets:’ These are sometimes used in the same manner as parentheses. The character coded “b” is a “reverse slash” - the mirror-image of the “slash” in Figure 3-3. The next character, “ * :’ is a compute symbol for depressing the “control key” on your keyboard. It canalso be used for a circumflex or exponentiation. Completing this set of characters, the character coded “e” is the “underlining” for a single character, and “f” represents the “opening single quotation” mark.

In Figure 35, the “lowercase” equivalents of the “uppercase” letters in Figure 3-4 are presented. These letters are also 10 characters per inch (CPI) in the Self-Test. Following the lowercase letters in this figure are four characters coded “a” through “dl’ The first and third are “braces:’ which provide an alternative to parentheses and brackets, especially in grouping mathematical terms. The symbol coded “b” is a special scientific symbol, to which you may assign meaning according to its use. Finally, the character marked “d” is the tilde sign or diacritical mark.

Self-Test

abed

abc:def ghi iklmnopqrstuvwxyz.~ : 1”

Figure 3-5.

This segment of the Gemini Se/f-Test shows you what the

lowercase letters look like, unless you command the printer to use

another type sty/e or a different size.

Figure 3-6.

The 96 italic characters form the third line of the

Gemini-15X Self-Test: the third and fourth lines with the Gemini-lox.

These characters are the italic version of the characters

individually identified in Figures 3-3, 3-4, and 3-5.

TAKE A CLOSER LOOK

Now that you’ve considered the 96 “standard” characters and the 96 italic characters, you’re ready to hook your Gemini up to your computer and get started.

If you wonder what these characters would look like if viewed

up close, you might want to take a moment and turn to Appendix K.

.._

/ / /\

INTERFACING GEMINI WITH YOUR COMPUTER

Your Gemini printer is a remarkable example of modern

engineering. A few short years ago, the information-handling capability built into Gemini would qualify the “printer” to be considered a “computer” of sorts. When Gemini is interfaced (“hooked up to”) your microcomputer, the results can be dazzling.

The characters identified in Chapter 3 are imbedded in

Gemini’s mad-on/ymemory(ROM’chips. Your computer doesn’t

need to tell Gemini how to print the set of dots that represents a certain character; your computer just needs to tell Gemini which

ones and where.

When your computer identifies the characters selected for printing, Gemini stores up to 816 bytes of data in its buffer at the same time that it’s printing. Gemini even knows when it runs out

of paper -

signaling you of the problem.

Before we explore interfacing Gemini with your computer,

let’s briefly consider how Gemini’s control circuit is configured.

As graphically illustrated in Apendix L (control circuit block diagram), Gemini features a central processing unit (CPU].

This CPU controls the electromechanical operations, such as the print head, carriage motor and paper feed motor. This CPU utilizes the random-access memory (RAM). It receives data serially, or in parallel, depending on which type of interface your system requires.

stopping the printing process and (if you wish)

INTERFACE OPTIONS

Gemini provides a parallel interface as standard. Parallel interface

is common to almost all popular microcomputers currently on the market. But some computers use serial processing transmission and require serial interface capability. As shown in Figure 4-1, Gemini is designed to accommodate either type of interface.

Gemini User’s Manual

Figure 4-1.

Parallel interface ,

(standard)

The Gemini printers are provided with the parallel interface

Control drive

circuit

CPU ROM RAM I/O

as standard equipment, with a serial interface available as an option.

The parallel interface is incorporated in the same printed circuitboard(PCB) as the contdcircuitboard. The optional serial interface board is constructed to be attached directly to the PCB and to fully reside within the body of the printer. If your system requires a serial interface, contact your Gemini dealer for purchase of the Gemini SBI-4010X serial interface board.

In the following section, we will discuss the parallel interface.

But first, let’s consider the DIP switches - where are they, what are they, and what do they do? So turn your printer around, and let’s look at the back.

lnferfacing Gemini with Your Compufer

: L..

’

The DIP Switches

The dual-in-line package (DIP) switch is a device that controls the

printer’s “patterns of thought? Several functions can be selected by appropriately setting the two DIP switches located on the

control logic board (Figure 4-2). DIP switch 2 can be set at the rear of the printer as shown in Figure 4-3. It is necessary to remove the

upper casing to set DIP switch 1. Please refer to Chapter 10 for instructions to remove the upper case. A status chart has been provided on the back panel of this manual to assist you in remembering the setting of each DIP switch in your printer.

Figure 4-2.

DIP switches on control logic board.

/Vote:Always set the DIP switches with the printer’s power turned

“Off?

Each pin in the DIP switch serves a distinct and separate

control function. The functions of DIP switch 1 are defined in

Figure 4-4. Figure 4-5 illustrates DIP switch settings for selection of the various character sets. Figure 4-6 illustrates the settings of DIP switch l-6,1-7, and 1-8 to choose international character

sets. Figure 4-7 contains the DIP switch 2 functions.

L.”

Ground

Terminal

Gemini User’s Manual

\ DYS-4 /

DIP Switch 2

Connector for Parallel Interface

Port Hole for Serial Interface (optional)

Figure 4-3.

DIP switch 2 controls (1) detection of when your Gemini runs

Power Cord

out of paper, (2) the effect of the CR codes on buffer-full printing, (3) 7-bit or 8-bit interface, and (4) automatic line feed.

Dip

Switch Pin No. Function

l-1 1-2 1-3 l-4 l-5 l-6 l-7

l-8

When “On”

When “Off”

Emphasized on 17 CPI

‘I, inch

Factory Setting - -

on on on

Figure 4-4. The eight switch settings and functions for DIP switch 1. Note

that switch l-1 and 1-4, as well as l-6 through l-8 are explained in Figure

43 and 4-6 respectively.

Interfacing Gemini with Your Computer

if DIP Switch 1-l

and l-4 are set as follows:

l-1

on on on off off off off

l-4

Then, your Gemini

will print the following

character sets

Standard ASCII

Download italic ASCII italic ASCII

Figure 4-5. The setting of DIPswitches l-l and 14 control the charactersets.

DIP Switch Settings

l-6

on off

off

l-7

on on off off

on off off

l-6

on on on on off off off off

Country

U.S.A. England Germany Denmark France Sweden Italy Spain

Form Length

11 inches 11 inches 12 inches 12 inches 12 inches 12 inches 12 inches 12 inches

Figure 4-6. By setting different combinations of DIP switches l-6, 1-7, and

1-8, you can select different international character sets and the form

lengths that are standard in those countries.

..::i

;:&j$ Swlt ch

.: . . . . >>> ,.,.

i;i;i;:;:>;::::

ii... :.. :j.

‘ii)j;j:ii!i; ::::::::+:

::.~:.:::.::::,

:::j::j-;:y: ;:;;<i;:;;:::: :g;.;:;:;:x

. . . . . . . ,.>,.)

$piiiii~~ :‘i::‘::\,$:::

::‘.::‘,:>j:::

::::::::‘:::::::

. . . . . :.:.>>>

:,::::.:.::::y ijis;;;;:; :::::::::,::::.:

::::::;:;::i:;:

;.;:i;:z::.;::

;g:‘:;;:::$

. . . ..:.: :.>>

;;;;g;i:i;i;i;

::::.:.:.: >>:

;:f~;;;j;g;;;

. . . . . . . . . >:.

:::::::j:.:.:.:

:::::::j:::::::

:::::::::::::.::

:::::::::,::.::

:::::y::.:::::’

i’;;:‘:i~$;;

i$$i:$;iii;

:::i::j::\ ::

~;>:h~Z:;i

;:;;:;;;:x::i

:>:.:::j:::.:

:::::j:::::i:::

i;:;:;:;:::;::

. . . . . . . . . . . :.>

~g$j;;

‘ii:::;:;:;:::i

g;;;;;;;;;;::;

:;::::..::::::::

.A.... :.:.:.>

:::j::;:.:.:::

::::::::::::::.:

:::::::::.;:lj

:::::::::::::::’

2-1

2-2

2-3

2-4

Function

No-paper

detection

Buffer full

Selection of the number

of bits

Automatic line feed

When “on”

Gemini signals when you are out of paper

The CR code is ignored, and one line of print data is stored until memory is full or the LF code is input

7-bit interface

CR code automatically performs line feed

Gemini User’s Manual

When “off”

The “out-of-paper” signal is not sent by Gemini enabling the printer to print with no paper.

Printing is

performed each

time the CR code

is input

8-bit interface

No line feed is performed by input of CRcode

Figure 4-7. DIP switch 2 is “on/off” toggles for four important printer operations.

The “on” position is when the toggle is flipped “up”; the switch is turned “off” when the toggle is pointed “down:’ The switches are numbered on Gemini, with the left-most toggle identified as “no. 1” when viewed from the rear and above.

Setting the DIP switches involves using the point of a baiipoint pen (or a similar tool that can serve as a small “finger”) by gently flipping each switch either up or down.

Appendices A through F respond to the need for setting the DIP switches for six popular types of home computers. Please refer to these appendices for information about the recommended settings for your computer. if your computer is not listed in these appendices, consult your computer’s user manual or your Gemini dealer.

; cr.

Interfacing Gem/d with Your Computer

Depending on the type of system you have, DIP switch

number 2-3 is an important DIP switch that affects computer

performance. For example, Apple operates on a 7-bit interface, and the IBM-PC requires an 8-bit interface.

L-

. .

CONNECTING THE PARALLEL INTERFACE

This section discusses hooking up your computer to Gemini, via the parallel interface.

A Look at the Parallel Interface Connector

When viewing your Gemini, as shown in Figure 4-3, the parallel

interface connector is just to the left of DIP switch 2. Take a moment to look closely at the connection. You will see that the connector is a metal band encasing a plastic spacer, with the center taking the form of a hollow rectangle. This rectangular opening is bordered both on the top and bottom with rows of 18 metal strips, called pins, that are set in the blue plastic spacer.

For more information about the pins in Gemini’s parallel

interface, turn to Appendix N at the back of this manual.

Each of these 38 pins supports an important function in your computer/printer interface, so the connecting plug must be compatible with the Gemini pin configuration.

The Connecting Plug and Cable

Note: The cable length should be as short as is workable to minimize signal loss.

Star Mfg. Co., Ltd. recommends a connecting plug by

AMPHENOL

The connecting cable should be a twisted-pair, ribbon-type cable. Appendices A through F provide information on acceptable connecting cables, including pin=out charts, in case you want to make your own connecting cable.

- product no. 57-30350.

Interfacing Gemini with Your Computer

Warning: Power to your computer and printer must be “off” before attaching the interface cable.

The parallel interface connector on Gemini is a rounded trapezoid,

with the top edge longer than the lower edge. The connecting plug

must be complementary with the Gemini connector; otherwise, it

won’t fit at all. Figure 4-8 shows the connection and the clamp pins for securing the union.

Gem/n/ User’s Manual

Figure 4-8. Securely attach both the clamp pins to ensure a good electrical connection.

Attach the other end of the connecting cable to your computer in accordance with the specifications for your microcomputer. If you are uncertain of what the connector should

look like, consult your computer’s user’s manual.

lnferfacing Geminl with Your Computer

SERIAL INTERFACE

The serial interface requirementsvary with the type of connector

and type of device to which Gemini is interfaced. The serial interface option can be purchased from your Gemini dealer and is accompanied by its own documentation.

INITIALIZATION

In Chapter 5, you’ll get a quick course in putting Gemini to work for you. But the first step is initialiling the printer for operation.

This can be accomplished in three ways. The easiest method

is to turn the power switch “off: then turn it back “on” again.

Another way is to apply the INPUT PRIME signal (parallel pin no.

31) to the interface connector (see Appendix ‘IN”). The third method is by transmitting the ESC @ code to Gemini, as discussed in Chapter 5 and 9.

Initializing Gemini is somewhat like “cleaning off the blackboard” to get ready for the next printing assignment. All special settings are cleared away and the “standard” character size, line height, and number of lines per page are restored. Altogether, six operations are accomplished when Gemini is initialized.

The print head goes to its “home” position (except in the case of ESC @).

The buffer contents are cleared.

The characters in download character

3. RAM are cleared (except in the case of ESC

es)-

Character pitch is set to 10 CPI or 17 CPI according to DIP switch 1-3.

Line pitch is set to 116 inch or 118 inch

5. according to the DIP switch 1-5.

International characters and form length are set according to the DIP switches 1-6, 1-7 and 1-8.

PUTTING GEMINI TO WORK FOR YOU

Your Gemini printer is an extraordinary machine. You can use it as a “super” typewriter, a graphics terminal, and as a regular computer line printer. Using standard routines on your computer, you can produce hard copy of program listings, computer memory dumps, and program outputs (text and graphics).

Gemini’s standard features include variable-pitch characters (that is, different sizes), adjustable line spacing, left and right margin control, settable tabs, italic type, and special character symbols. High-resolution graphics can be created using the bit image column scan mode.

In this chapter, you will get an accelerated course in how to produce most of Gemini’s special effects, If you stop reading this manual at the end of this chapter, you should know enough to be able to dazzle your friends with your command of the Gemini. So let’s get started.

TALKING TO YOUR PRINTER

When you type on a conventional typewriter, your fingers tell the

machine which characters to print by striking different keys. You can control the margins, tabs, and spacing of the lines by setting

various mechanical controls. If there are removable-type

“elements” on your electric typewriter, you can change the type style to italic or special symbols (such as math or Greek).

Aside from the DIP switches and control panel buttons atop Gemini, there are no controls to set on your printer to produce various printing effects. Everything is controlled from your computer by means of electrical signals carried via the connector cable. In addition to telling the printer which characters you want to print, we send Gemini coded messages that change the type size and style, set tabs, vary the line spacing, etc.

In Chapter 3, we discussed the Self-Test and used a “lettercode” corresponding to the individual printed characters. That simple type of coding may have worked there, but another (more sophisticated) coding is required for your computer to efficiently communicate with your Gemini.

The ASCII Code

Every letter, numeral, and other character that is sent from the computer to Gemini is transmitted in the form of a number code. A standardcode was agreed upon to allow greater compatibility

among the hundreds of different types of computers and peripherals. This industry-wide uniform code is called the American Standard Code for Information Interchange, or ASCII (pronounced “ask-key”)

Please turn to Appendix K and you will see each character printed by Gemini and a corresponding ASCII code. The decimal number “65” is the code representing the uppercase letter “AI’ The lowercase “a” is represented by “971’ For every character, there is a corresponding code number.

The ASCII code numbers for the uppercase letters, numerals, and punctuation marks are fairly well standardized. Thus, most computers share the same ASCII codes between 32 and 127.

Unfortunately, the rest of the codes (128 through 255) are nowhere near standardization in all computer systems.

Gemini User’s Manual

Nofe:This is a timely opportunity for you to review the manual that accompanied your computer and to compare your computer’s ASCII character codes with Gemini’s. Somewhere in the back of your computer manual, you should find a table or chart of ASCII character codes. Compare the chart with Appendix H at the back of this manual. Mark the characters that are different, for future

reference.

Function Codes

Besides letters and numerals, you can send special commands

to functionally control printing operations. These codes are

identified variously as “function:’ “control;’ and “command”

codes, but they serve the same purpose. In this manual, we call

them function codes and they are listed in Appendix M and in the Quick-Reference chart (on this manual’s inside back cover).

Chapter 9 explains what these codes accomplish. For now, you need only note that some codes are repetitions of others. Because not all computers can send all the ASCII codes, Gemini accepts any of several function codes to cause the same effect.

Putting Gemini to Work

Transmitting the Codes

The easiest way to transmit functional control codes is to build them into the software program that sends the regular codes for

letters and numerals. Sending the control codes to the printer by building them into the program allows you to change the printing instructions during the program. This gives you total control to print what you want, the way you want to print it.

You can also send control codes to the printer using the computer system’s “command level” functions before running a program.

All of this discussion about sending codes for special printing effects should not be confused with the “printing codes and commands” that are a part of commercially available word

processing software programs. Word processing programs have built-in codes for some (but not all) special effects, such as bold type or underscoring. But Gemini can do more “tricks” than the word processing programs know to request. “Recycling” (that is, fixing) word processing programs so they are fully compatible with Gemini’s capabilities requires “Patching”the programs. All this is discussed in the section entitled “Word Processing Software:’ toward the end of this chapter.

Because of its simplicity, availability, and popularity, we will use BASlC(a computer language) to demonstrate and learn about the Gemini printer. Other languages, such as PASCAL, COBOL, FORTRAN, etc., could also be used, but to keep this training exercise short and simple, we’ll stick to “BASICS?

If you are unfamiliar with BASIC, you might start by turning

to the user’s manual that came with your computer. There’s almost certainly a chapter or two about BASIC. You might turn your

attention for a few minutes to reading in your computer’s manual

about how to set your computer up for running a program in

BASIC.

Internally, your computer uses a binary code (sometimes

expressed as “zeros” and “ones”) to convey information. The ASCII codes in Appendix H are decimal(in that they are based on ten numbers - 0 through 9), and hexadecimal (based on

16number mathematical system). In our sample programs, we’ll use the ASCII decimal equivalents.

In BASIC, the CH/?$function is used to convert the decimal

ASCII code into your computer’s binary code. Thus,

LPRINT “A” means the same as LPRINT CHR$ (65)

The CHR$ function (pronounced “characterstring”) allows you to transmit special characters and ASCII control codes that are not

directly available through your computer.

The Problem with BASIC

The “basic” problem with BASIC is similar to the problem with the ASCII code: While there are many program statements that are standard, there is no standardization of the BASIC language.

The IBM-PC, TRSBO, Atari, and many other computers (as well as Microsoft BASIC for CPIM) use the statement PRINT to send information to the screen, and the statement LPf?IIVTto send

information to the printer.

The Atari can also use a variation of the LPRINT statement,

requiring (for example) that a file number(such as # 1) be assigned to the printer.Therefore, PRiNT# 1 sends information to the printer, and PRINT sends information to the screen.

Other BASIC versions, such as Applesoft and CBASIC for CPIM, use PRINT to send information both to the screen and to the printer. Using the PR#l statement before PRlNT sends

information only to the printer, and using PR #0 sends information only to the screen. Confused?

The example programs in this manual will use IBM-PC

Microsoft BASIC. For those of you with other computers, we have included appendices (at the back of this manual) for the Apple II Plus, Atari, TRS80, Commodore VIC-20 and C-64, and Osborne

computers. These appendices discuss the modifications

necessary to run the example programs. If your computer is not

included in the appendices, look at the appendix for the system that seems most similar to your own, and look at the section in your ccmputer’s instruction manual pertaining to printers.

Gemini User’s Manual

GETTING “ONLINE”

You can’t learn to swim in an armchair. The only way to use BASIC

is to try it. So, after you’ve reviewed the chapter on BASIC in your

Putting Gemini to Work

computer manual, try this exercise to “test the water:’ Enter this

simple program:

LPRINT CHR$(14); “BASIC”

then, hit the return (sometimes called the “enter” key). That one-

line program establishes communication between your computer and Gemini. Now enter this line of text:

LPRINT CHR$(27); “Q”; “If I can do this,

After entering this line, when you hit the return key (the “enter”

key on some systems), you’ll be sending function codes and text

to your printer. Hit the return and see what happens. If your Gemini

prints out your simple program, you know that you’re ready to take

the plunge with the more advanced sample programs that follow.

I+ I can do this, I can do anything!

If, for some reason, Gemini didn’t get the message and respond with action, you might do well to turn your computer off and just read over the remainder of this chapter. A wealth of information about printer capabilities is presented, even if you don’t qualify as a “programmer?

If this simple test worked out well for you and your computer

system, get ready because in the next example, you’ll dive off the

“championship” board and try a double back flip into the deep end.

I can do anything!”

1 E

1 1

Getting Ready to Diwe In

Check the position of the printer DIP switches before proceeding with the next example. For the IBM-PC, DIP switch number 2-1 on your Gemini should be “on:’ and the other three should be “off?

Note: Check with Appendices A-F for information about setting

the DIP switches for various computer systems, as well as for

modifications that may be required in order to run the following

program.

If you are using sprocket-fed fan fold paper, roll the paper up

until the perforation is even with the ribbon guide.

Note: Because the paper drive is engaged when the power is “on:’ you should only adjust the paper position when Gemini’s power

is “off? Moving the platen (by turning the platen knob) when the power is “on” may damage the paper-advance mechanism.

Gemini User’s Manual

Turn your computer “on? Follow the set-up requirements, if

any (such as the selection of the printer interface mode). Load

BASIC and turn “on” your Gemini. The “Power;’ “Ready:’ and

“Online” lamps should be lit on Gemini’s control panel.

Type in the reference-program listing, Figure 5-l making the

modifications outlined in the appendices for your computer

system.

Note: You should “proofread” each line you type in before entering

it. If you want your program to look like Figure 5-2, your program

listing must lookexactly like the one shown in Figure51 (subject,

of course, to minor changes for computers other than the IBM-PC).

Before You Run the Sample Program

The program you just typed in was a long one, but it illustrates about one-half of the features available on Gemini. Before we run

the program, let’s utilize Gemini as a line printer. Create a program listing by typing LLIST. You can use this listing to double-check that you have correctly entered the reference program (Figure 5-l). If you discover any errors, correct them. Then create another listing by entering:

WIDTH “LPTl:“, 255

LPRINT CHR$(15)

and then,,

LLIST

The WIDTH command told the BASIC program that your printer could print as many characters as it wants per line. The CHR$(15) was sent to tell Gemini to print in “reduced” type of 17

characters per inch (CPI). By using the reduced type, full 136character output (Figure 5-l) can be printed on the Gemini-lox and 233 characters on the Gemini-15X.

Putting Gemini to Work

!O WIDTH “LPT!: “, 132 20 ESCWHR4(27) : LWCHR$(lO! : FFWHRSIl?) : CRl=CHR$(lS)

30 PICM=ESCI+‘B”+CHR4 (1) : ELITE)=ESCWB’+CHR$ (21 : COHPI=ESCWB’+CHRI (3) 40 SUPERI~ESCS+‘S’+CHR$fO) : SUB$~ESCC+‘S’+CHRt (1) : MNSS=ESCSt”T”

SO ITGLIC(1ESCStCHR4(52I : STbND4=ESC$+CHRI(SS)

60 WIDEWHR#(14) : CINWIDE4=CHRI(20) : PRSE?GESCl+‘C”

70 EMPH+ESW”E’ : CEtiPH$=ESCW’F” : DBLSI=ESCW”6” : CDBLS$=ESC$+“H’

90 LPRINT PRSET$;ESCI; “R’;CHRSflSI:FFI 90 FOR I * 1 TO 2 !OO IF I = 1 THEN LPRINT WIDEI;’ 6MINI STANDARD TYPE STYLES’;CANWIDE$;LF$ 110 IF I = 2 THEN LPRINT ITALICS$:WIDE$:”

6EflINI ITALIC TYPE STYLES’ICANWIDE$;LFI

120 FOR N = 1 TO 40 : LPRINT CHRS(231) : CHR4(232) ; : NEXT N : LPRINT : LPRINT

130 LPRINT” 140 FOR N m 1 TO SO : LPRINT CHRSt241) I : NEXT N : LPRINT

17 :oi 12 cpi 10 cd S.5 cpi 6 cpi 5 cci"

150 !SSl$=" IIBC" : tlS62(="Xx' : !!SSS$='Yy" 160 FOR J = 1 TO 4 170 IF I n 2 THEN LPRINT ITALICS:

180 IF J = ! THEN LPRINT COf!P$;“norral

“;

190 IF J = 2 THEN LPRINT CONPI:"doublr #trike ":

200 IF J * 3 THEN LPRINT COflPti"tmpharirnd

210 IF J : 4 THEN LPRINT COftPI:“double strike “: 220 FOR K = 1 TO 6 250 IF K = 1 THEN LPRINT CONPt; ?40 IF K = 2 THEN LPRINT ELITES: 250 IF K = 3 THEN LPRINT PICM; 260 IF K = 4 THEN LPRINT COhP$:NIDEI: 270 IF K = 5 THEN LPRINT ELITE$:WIDE$: 280 IF K = 6 THEN LPRINT PIC/I;WIDE4: 290 IF J = 2 THEN LPRINT DBLS8; ZOO IF J = 3 THEN LPRINT ENPHS; 310 IF J = 4 THEN LPRINT DBLSSiEltPH$: ?20 LPRINT NS6l~;SUPER~:~S624~CbNS(ISUBl:NS631:C~NS~:CDBLS~: 330 IF K 1 3 THEN LPRINT CANWIDEJ; 340 NEXT K

345 IF Jm2 THEN LPRINT Lflr 350 IF J = 4 THEN LPRINT ESCS:‘6’:CHR4~9):LF4;COMP~:” 360 LPRINT PRSET4 370 NEXT J

+ ‘:CRt; “emphasized ‘;

380 LPRINT STRIN6S (5,101

390 NEXT I 400 LPRINT FFI : WIDTH “LPTl:“,SO :END

L..

Figure 5-1. This sample program (written in BASIC for the IBM-PC, but amendable to any personal computer) is shown here in reduced or “com-

pressed” type and will produce the “Printing Effects”shown in Figure 5-2.

Run the Reference Program

Because we left the printer in the 17-CPI mode at the end of the sample program listing, we need to reset Gemini before running the program.

To reset (initialize) your printer, turn the power “off:’ then back

“on:’ Another way to initialize Gemini is via the software message:

LPRINT CHR$(27); “a” A moment ago we talked about plunging into this sample exercise The way to make that plunge is to enter:

Gemini User’s Manual

RUN

ncrnal

double str:ke

ewhasrzed

double st:lkc

emvhasi:ed

---,-~-------..-“-----~-~-d-~-~-~-~-

nor,rl bBC”‘Y,

doable strike

cqhrriztd REP’“,

douhlc strlkr

rroharrred

ABC"",

4BCx-,,

MC’-“, ABC”““,

RBC”,,

MC”““,

MC%, pBp-,,

I3EMINI ITAI-IC TYF'E STYLES

17 cp: 12 cc1 10 CDI 8.5 cp1

APC”-Y”

bIE”‘,,

RRCX-,,

4PC”-Y”

w=,,

RbTx-,”

&BP”“,

ABC’=“,

FIBCXxYy ABCXxYy

ABCXxYy

.-.-------

ABCXXr,

RRC”- Yv

6?BCXxY y RBCXxYy

RBCXxYy

ABCXxYy

ABCXxYy FIBCXnYy

CIBCXxYy

------~-~-l-~-~~-~-~-~-~~~-~-_ -

RBCXxYy

RBCXxY y #BCXxY y

RBCXxYy

AHCXX Yy fA%CX:-: Yy

ABCXX Yy

CSBCXXYY CIBCXxYy

L CD1 5 CIpl

Ai3C.x.s Y y ARCX .x- Y y

ARCK.\~ Y y

UBCXXY y RRCXxY y

FIRCXxYy

ABCXxYy

ARGXxYy JQRCXXYY

Figure 5-2. This sample run program (shown here at two-thirds actual size) demonstrates standard and italic type sty/es in six sizes (measured in characters per inch) for normal, double-strike, emphasized, and doubleemphasized types - each with superscripts and subscripts.

There it is, a reference sheet that summarizes the various type styles that Gemini can produce. If your printout looks like Figure 5-2, great! Turn your printer “off:’ advance the paper, and tear off the tables. We will now analyze the program and printout to learn

how we managed to do what we did.

On the Other Hand. . .

If you made a typing error that caused the program to “belly flop:’ or if your printout looks strangely dissimilar to Figure 5-2, you should reset Gemini and try again. The printer may have received an unwanted function code. Or, perhaps the communication became garbled between your computer and Gemini. Whatever the problem, reset (initialize) Gemini and try again.

ANALYZING THE PROGRAM

In this section, we’ll analyze the program you entered, using Figure

5-l as your reference. Before we start, you might want to SAVE the

program on disk or tape to avoid having to retype it if you ever want

to use it again.

Let’s begin by considering line 10, shown in Figure 5-l. This

line tells the BASIC interpreter that the printer will accept 132 characters per line. This prevents BASIC from tossing in extra carriage returns and line feeds where we don’t want them.

Lines 20 through 70 are used to set some printer controls to

more easily remembered codes. The escape code (which is ASCII decimal code 27) is set to ESC$. The command that tells the printer to advance one line (ASCII code 10) is set to LF$. The variable FF$

is set to ASCII code 12, a command to Gemini that the printer

should advance to the top of the next page. Thedefault value, set

by power “on” or receipt of the software reset, is 66 lines per page.

Line 30 sets the printer command to change type size. The format of this command is ESC$ + “B” + n, where n can be 1, 2, or 3. If n is 1, the type size is 10 characters per inch (CPI). This

is the type size of a standard typewriter’s print, called “pica? Pica is the type size you select when Gemini is initialized, until and unless you ask for different type size. If n is 2, the type size is 12 CPI, the same size as “elite” typewriter print. If n is 3, the type size is 17 CPI, the size of the compressed type we used for the listing

in Figure 5-1.

Gemini User’s Manual

Wait a minute. Didn’t we use the command code CHR$(15) to shift into compressed type? That’s right; there are two ways of shifting into compressed type: - the single-character command; CHR$(15), and the three-character command; ESC$ + “B” + 3. [Actually, that’s CHR$(27); CHR$(66); and CHR$(3), if you check the

ASCII code table in Appendix I.] The command CHR$(18) can be used to shift the printer from compressed mode back to normal pica-size print.

Line 40 sets some variables that allow shifting into (and out

of) the superscript and subscript mode. Superscripts are characters that are printed above the regular line of type, such as the “2” in E = MC?. Subscripts are below the line, such as the “2” in H,O. On some printers, the “supers” and “subs” are produced by rolling the paper up and down a half-line, printing the superscript or subscript, then rolling the paper back to its original position.

Gemini prints “supers” and “subs” using special characters

that are small enough to convey the scripting in the space

normally utilized by the ascenders ‘such as the top of a “t”) and descenders (the lower part of the letter “g”). The scripting characters are printed “high” or “low” on the line to produce a

professional-looking scripting effect - without having to roll the

paper up and down by hand.

ESC$ + “S” + CHR$(O) causes the printer to operate in its superscript mode, and ESC$ + “S” + CHR$(l) initiates the subscript. Either mode is cancelled by ESC$ + “T” command actually, CHR$(27); CHR$(84).

Line 50 sets the command to produce italic type. CHR$(27);

CHR!§(52) causes Gemini to print in full italic all text received subsequent to the command, until the ESC$ + CHR$(53) command [or printer reset = CHR$(27); “@“I is received.

Line 60 sets the command to double the width of the

characters that are being printed. CHR$(14) sets the double-width print mode, and CHR$(20) cancels the double-width mode. ESC$

+ “W” + 1 [which is the equivalent of CHR$(27); CHR$(87);

CHR$(l) command] also sets the double-width mode; in this case, ESC$ + “W” + Ocancels the double-width mode. You might note that with the three type sizes, plus the double-width mode, we have six different character sizes from which to select. On the end of line 60 is the printer reset command we call “PRSET” in this program.

Putting Gemini to Work

Compressed Elite Pica (normal) Double-width Compressed Double-width Elite Double-width Pica

17 CPI 12CPI 10 CPI

8.5 CPI 8CPI 5CPI

Line 70, the last line of our definitions, contains functional commands to control the way the type is printed. In emphasized printing, Gemini prints the characters once, then goes back and reprints them (with the dots offset by one-half dot). This is explained in the next chapter, but for now just remember that both emphasized and double-strike involves printing each character twice.

In line 70, ESC$ + “E” puts the printer in the emphasized mode, and ESC$ + “F” cancels the emphasized printing. ESC!§

+ “G” puts the printer in double-strike mode, and ESC$ + “H”

cancels that mode.

Both emphasized and double-strike can be invoked at the same time to produce maximum-density printing. Some

restrictions apply to the use of emphasized printing and some of the other print commands. We’ll go over these restrictions when we examine in detail the tables printed by this program.

Line 80 is the first line of the program that sends “text” data

to the printer. What information are we sending Gemini? First, we

send the character string PRSET$, telling Gemini to reset

according to the command CHR$(27); “@1’ Even though we didn’t

need to reset Gemini after printing the listing in compressed type,

it’s a good programming practice to make sure your printer is in

its initialized state at the beginning of your program.

The ESC$; “R”; CHR$(15) sequence in line 80 tells Gemini to advance the paper 15 lines after the form-feed command is received. The default for the beginning line (or “header”) is the first line on the page. The FF$ variable sends a form feed command to Gemini. This line is used to cause Gemini to skip one page of paper (that’s 66 lines with conventional fanfold sprocket-fed

Gemini User’s Manual

paper), then skip down 16 lines from the top of the next page. So where, you might ask, did the extra line come from? BASIC inserts a carriage return (CR) and line feed (LF) at the end of every LPRINT

statement, unless the last character in LPRINT is a semicolon (;).

Line 90 starts the major loop of the program, which causes the normal and italic tables to be printed. If the variable “I” is equal to the number 1, then the message on line 100 is printed. If “I” equals 2, the message on line 110 is printed. Let’s lookat line 100:

LPRINT WIDE$; “GEMINI STANDARD

TYPE STYLES”; CANWIDE$; LF$ You might ask: What does WIDE!$ cause to be printed? The answer is not “what:’ but “howl’WIDE$ is set (on line60) to CHR$(I4), the command for the double-width printing mode. Look at Figure 5-2 to verify that.

The CANWIDE$ string cancels the double-width function

(also set on line 60). The semicolon between character strings

causes the strings to be printed without anyspaces between them.

The LF$ string causes a line feed; the LPRINT statement produces another carriage return and a line feed because it does not end with a semicolon.

Line 110 causes a similar message to be printed, but this time we did not invoke the italic print style by sending the ITALIC$ command string to Gemini at the beginning of LPRINT statement.

Line 120 looks interesting, because it serves an interesting purpose. Line 120 is a loop from 1 to 40 that sends two characters to Gemini for each cycle of the loop. What, you might ask are the two characters: CHR$(231) and CHR$(232)? To find out, turn to Appendices I or H. ASCII code numbers 231 and 232 appear to be

what, in a gymnast’s parlance might be called “uneven parallel

bars:’ Number 231 is the upper bar, and number 232 is the lower bar. These two characters are part of Gemini’s “6 x 6” graphics

set (as explained further in Chapter 7).

The two LPRINT statements at the end of line 120 cause two

line feeds after the loop is completed. Did you notice the

semicolon at the LPRINT, inside the loop? Without that “;” a carriage return would be generated after each printing of these two characters. With the semicolon, we get the alternating row of short bars that serve as decoration beneath the table titles in Figure 5-2.

Line 130 is straightforward; it prints the column headings for

the table. Because the printer has been set to produce these headings in I = 1 and in I = 2, the headings appear in normal and

‘-

Putting Gemini to Work

italic type, respectively, in Figure 5-2. You might note that the

decorative graphic characters are unaffected by the italic control,

and the italic mode is resumed after 6 x 6 characters are printed.

Line 140 is similar to line 120, and serves as one way of

drawing a line across a page.

Line 150 sets three character strings in preparation for the printing that follows. The first string, “ABC:’ is printed in normal script. The next string, “Xx”, string, “Yy:’ is printed in subscript. If you prefer other characters

(for example, your name) to be printed in another version of Figure 5-2, change these strings and rerun the program.

Line 160 starts the loop-over printing modes. Line 170 puts the printer into italic type when I = 2. This is required because we will use the printer-reset to clear the print modes at the end of this loop. The printer-reset causes Gemini to go back to its initial power “on” state.

Lines 180 through 210 print row headings for the tables, on the left side of the lines illustrating the print modes in Figure 5-2.

For J = I, the print mode is normal. J = 2 produces the double-

strike effect. The print is emphasized as a result of J = 3. With J

4, Gemini produces a combination of double-strike plus

emphasized type. You might also note that we set the row

headings in compressed type to conserve space so that the tables

would fit on lO-inch-wide paper.

Line 220 starts the inner loop, which prints each line of the

table. Lines 230 through 280 set the six different print sizes. If

K = I, line 230 sends the COMP$ command to Gemini, which causes a shift into the compressed print mode. If K = 2, then line 240 sends the ELITE$ command to the printer. If K = 3, line 250 sends the PICA$ command, thus directing Gemini to print in normal (IO CPI) type size. The question might arise: Could we use the PRSET$ mode instead? If we did, it would be necessary to reset the italic mode before printing the table characters when I = 2. When K = 4, line 260 sends both the COMP$ and the WIDE!§ commands, causing the printer to shift into 8.5 CPI.

Lines 270 and 280 cause Gemini to print 6 CPI when K = 5,

and 5 CPI when K = 6.

Line 290 invokes the double-strike mode when J = 2 by sending the character string DBL$ to Gemini. You may recall the DBL$ is equal to ESC$ + “G” or, equivalently, CHR$(27); CHRS(71).

Line 300 sends the emphasized mode command to the printer

is printed in superscript. The third

Gemini User’s Manual

by of character EMPH$. J = 4, line 310 shifts Gemini into the double-strike and emphasized mode by sending both the DBL$ and EMPH$ commands.

Line 320 is the heart of the program. This line prints out the entire table. The rest of the program prints the titles and headings, or sets the print size and style. In line 320, the character string

MSGl$(set to “ABC” by line 150) is printed in whatever mode the printer is in as a result of preceding the transmission of the SUPER$ command string (remember line 40?) and the character string MSG2$ is printed. The superscript mode is cancelled by sending the CANS$ string [CHR$(27); CHR$(84), or by ESC$ “T”].

The subscript mode is invoked by sending the SUB$

command string. The third character string in line 320, MSG3$

(which is “Yy”), is then printed, only to be cancelled by the CAN$ command again. Finally, the double-strike print mode is cancelled.

Why did we have to cancel the double-strike mode? Where did we invoke it? In order to make the half-height superscript and subscript characters more legible, they are automatically printed

using the double-strike print mode. Cancelling the superscript or

subscript does not automatically cancel the double-strike mode.

You might notice that line 320 is used six times to print one

line. Line 330 is used to cancel the double-width command when K is greater than 3. This is done because the double-width command is sent when K is equal to 4,5, or 6, by lines 260,270, and 280.

Line 340 is the bottom of the inner K loop. Line 350 is

responsibie for printing the words “+ emphasized” after the last

line of each table. You might want to direct your attention to Chapter 9, or to Appendix M, to learn the purpose of the ESC “A” n functional control code. We used this control code to reset the

spacing between lines.

When Gemini is initialized, the spacing is set to one-sixth of an inch, when DIP switch 1-5 is “on? (This is the standard “singlespace” of a conventional “pica” typewriter.) With Gemini, this x-inch spacing allows a “half-character” of spacing between lines of text.

The ESC$; “A”; n function code allows us to vary the spacing between lines. When the spacing control codes are sent to the

printer, the spacing for the line feed is set to n/72 inch. Thus, if n is set to be 12, the spacing in 12172, which is I/, of an inch. If n is less than 12, the spacing between lines will be less than the normal

Putting Gemini to Work

default spacing. If n is greater than 12, the spacing will be larger than normal.

In line 350, we set n to equal 9, with the result that the line spacing is changed to 9172 or ‘/B inch. A line feed is set to move down (or, to be more correct, “advance the paper”) 1/8 inch, then return the print head to the first print column (it’s “home” position). The printer is shifted into the compressed mode because of COMP$, the ‘I+” is printed, followed by another carriage return and line feed. The word “emphasized” is then printed, and line 350

has done its job.

Line 360 clears all the previous print function codes and

restores Gemini to its initialized values. Line 370 is the bottom of

the J loop.

Line 380 is one way of advancing the paper by multiple line feeds. The STRING$(5,10) function is used to return a string of length n, whose characters all have the ASCII code of the first

character in A$. Because the line-feed command is a single character, this function allows us to skip multiple lines. Vertical tabs and other line-spacing controls are discussed further in Chapter 9.

Line 390 is the bottom of the outer loop. Line 400 finishes up the program by sending a form-feed command to Gemini, resetting the “line printer” to an 8Ocharacter width. With that, line 400 ends the program.

Now that we have considered the causes, let’s look at the effects. In the following section, we’ll interpret Figure 5-2, amended to show the 88 type styles and sizes that Gemini can

provide for practical applications.

WHAT WE’VE LEARNED GEMINI CAN DO

So far in this chapter, we’ve learned that Gemini can do more than the most popular word processing software can handle. To enjoy the full range of type styles and sizes, you need to create computer programs in BASIC (or other computer languages) to send functional commands to Gemini. Or, as described in the following section, you can “patch” your word processing software so it’s smart enought to manage Gemini properly.

Figure 5-3 is an amended version of Figure 52 that shows the

88 variations of type sizes and sfy/es for the alphanumeric

Gemini User’s Manual

characters. (“Alphanumeric” means all the characters that are the letters in the alphabet and numerical symbols for numbers.) The difference between Figures 5-2 and 5-3 is that the latter has had -some of the superscripts and subscripts eliminated.

The “supers” and “subs” are designed for normal and double- -

strike type in IO, 12, and I7 CPI. Superscripts and subscripts were

not intended for use in the emphasized mode. When you double

the width of the characters (5,6, and 8.5 CPI), the “scripts” are distorted to the point that they are garbled. They weren’t designed for double-width printing, and aren’t needed.

By examining Figure 5-3, you can see at a glance that Gemini

can print in six type sizes, between 5 and 17 characters per inch.

Gemini prints in roman type (the upp.er table) and italic type (the

lower table). In addition, Gemini produces quality superscripting in 20 modes, as well as quality subscripting in an equal number. If you add up all these typeface options, you’ll count as many

Gemini text options as there are keys on a piano.

Figure 5-3 also demonstrates a hint of Gemini’s6 x 6 graphics capability. If you look in Appendix K at ASCII code numbers 224 through 255, you’ll see an enlargement of the full set of 6 x 6 graphics. The straight line that separates the CPI column headings from the body of the tables in Figure 5-3 was produced by repeating ASCII code number 241 across the page. The alternating

sequence of ASCII code numbers 231 and 232 produced the graphic embellishment that appears under the “standard” and _

“italic” table titles. In Chapter 7, you’ll learn more about what you

can do with the 6 x 6 graphic character set.

Although the “ABC’s” in Figure5-3vary in intensity, slant, and - width, they are all the same height. That’s because all Gemini’s alphanumeric characters are printed using a fixed-height matrix.

The matrix is represented by the numerals that appear on the first page of each chapter in this manual. A reduced version of that

-. chapter-identifier appears at the top of this page. You can see that the matrix (or grid) is nine rows high and five rows wide (with some dots on the lines between columns). The compressed and double-

width modes print the same character matrix, but with the width of the horizontal columns shortened or expanded, respectively.

If you are observant, you might notice that the “ABC’s” across each row in Figure 5-3 appear to slope slightly downward from left to right. In your everyday printing, you won’t get this effect; your lines of text will be perfectly straight. The reason for

Putting Gemini to Work

the sloping in this sample program is the frequent use of superscripts and subscripts.

When you print “supers” and “subs:’ Gemini executes the “scripts” in the double-strike mode. Double-striking involves printing the characters once, then reprinting them 11144th inch lower. One one-hundred-and-forty-fourth of an inch isn’t even detectable (unless you have the eyes of a hawk).

In most printing situations, you won’t use superscripts and subscripts more than once or twice a line (if at all). Thus, printing the remainder of a line 1/144th or 21144th of an inch lower would not be noticeable. In our sample program (Figure 5-2), there were I2 “supers” and “subs” per line - giving a total of 121144ths (or

GEMINI

_____ -- . .._ ----. NVDa!

double strike

raphrr!zPd

double strlkr

ophaslzrd

17 cp1 12 cc1

bBC”‘,.

DW’,,

RBC”,,

ttw,,

.----.-.-.-

ABCX-Y,

MC*-,,

RRC”-Y*

RRCX-Y,

I-l-aI-IC

1’:’ co1

ARCXXY,

RRCX- Y” ABC

RBC RBC

TYF’E STYLES

2.5 cpl ~--

/?)BC

c)BC

ABC ARC URC

t cpl 5 cpl

ARC

UBC

URC

RRC

Figure 53. The sample program’s results, amended to show the 88 viable options for type sizes and sty/es using Gemini.

Gemini User’s Manual

1/12th) of an inch difference between the beginning and end of the line.

By examining the lower table in Figure 5-3, you’ll see that the

same options and parameters apply to italic type as to standard type.

WORD PROCESSING SOFTWARE

Word processing is the family of programs that package text in

forms understandable by your microcomputer, its display monitor, and various printers. Popular word processing programs include Wordstar, the Electric Pencil, Easywriter, Word Handler, Perfect Writer, etc. (Note: Each of these programs is the copyrighted

property and registered trademark of the companies that own them. They are mentioned here only as examples of commercially available word processing programs.)

Most of the popular word processing programs were written a few years ago, when printers were simpler devices, capable of performing far fewer options than are available with Gemini.

For example, most current word processing programs can send function codes for printing “bold” type (double-striking). To accomplish this, the word processing software sends multiple

instructions (initiated by keyboard commands such as “control-

B” or “control-E”). When older printers receive these instructions, they print a word, then get the signal for their printing mechanism to back up, then respond to another signal that tells the “dumb”

printer to print the word again. With Gemini, the function code ESC

“E” tells the smart printer to automatically double-strike using

the LPRINT command conveyed in BASIC.

Don’t be discouraged if you bought a word processing package and it seems inadequate to utilize Gemini’s full capabilities. Gemini can do just about anything your word processing software can tell it to do, and then some. There are four solutions to the problem.

The BASIC Solution

One solution to the limitations of word processing software is not to use it when you want to make full use of Gemini’s potential performance. You can learn BASIC and put it to work.

Putting Gemini to Work

Even without “mastering” BASIC, you’ll be able to work

wonders with Gemini, a.s you’ve already learned in this chapter.

User-Patching Your Software Program

“Patching” is the term used to describe making changes in an existing word processing program so that it can make fuller use of Gemini’s capabilities. To accomplish patching, refer to your word processing software user’s manual. The manual should have a listing that demonstrates “user-patchable” changes you can

make in the program.

A word of warning: You need to be computer-wise to

successfully patch an existing word processing program. Before you start, it’s probably a good idea to make a copy of your word

processing program and attempt patching the copy. That way, if you make an error, you’re only out the time you invested and

haven’t hurt the “original?

Software Patching Setvices

Another solution to the problem of software/printer incompatibility is to turn to one of the “software recycling” services that advertise in hobbyist computing publications.

For a modest sum, they will “recycle” your software by performing the patching operation for you. Many of these services invite you to mail them your word processing software (and, of

course, a check), and they’ll send you back a “tailored-to-fit”

program on your same diskette(s).

The Creative Solution

If you made it through the program listed in Figure 5-1, you should

be able to create a simple program that serves as

“Your Own Word Processing Software System.” (The title’s a bit long; you can always “word process” it to something short and snappy.) Even if you didn’t successfully execute the sample program, don’t be afraid of trying this task.

Remember: You may never know if you can do something unless

you try.

Gemini User’s Manual

10 CLS:KEY 3FF:DM AS(24,BO) 20 cLs:X~l:Y:l 30 SOSUB 1SO:LOCATE X,Y:PRINT “C” 40 B$=INKEYI:IF B+“’ THEN 40 SO IF B$aCHR¶(S) THEN CL&END 50 IF BI=CHRI!lB) THEN CLS:SOBUB 200:60TO 20 70 IF BJ=CHRl(lb) THEN 6010 220

“C”: : SOT0 40

90 IF BWHR((4) THEN SOSUB 130:GOT0 40

100 LOCATE X,Y:PRINT BJ;:RI(X,Y)+:Y=Y+l

110 IF YgBO THEN A$(X,Yl=CHR((l3):BEEP:X*X+l

120 LOCATE X,Y:PRINT “@“;:GOTO 40

130 LOCATE X,Y:PRINT ” “i:Y:Y-1:IF Y=O THEN

!35 A5(X,Y)=“”

140 LOCATE X,Y:PRINT “~*;:RETuRN

!50 LOCATE 25,2:COLOR O,?:PR!NT ” ^P) printer “::

160 LOCATE 25,17:COLOR 0,7:PRINT ” ‘D) delete “::COLOR 7,0 170 LOCATE ?S,JQ:COLOR O,?:PRINT @ ^A) restart “::COLOR !,O 180 LOCATE 25,5!:COLOR O!?:PRINT ” “El exit “::COLOR 7,o :90 RETURN

200 LOCATE !0,30:PRINT “olease stand bv “;:FOR I=1 TO X:FOR Jzl TO SO:M(I,J)=““:

NEXT: NEXT: RETURN 220 LPRIN? CHRb(27) : ‘@” 230 CLS:LOCATE 25,?:COLgR 0,7:PRINT ” Clonnand “: :LOCfiTE 25,16 ‘40 PRINT ” Pjrint

c 250 G$=INKEY):IF 65=“’ THEN 250 200 IF 6l=“P” THEN SOSUB 310 270 IF G§=“C” THEN GOSUB 320:GOT0 230 280 IF S$=“R” THEN 6OSUB 300:GOT0 30 290 GOT0 250 300 CLS:FOR 111 TO X:FOR J=l TO BO:LOCATE 1,J:pRINT M(I,J);:NEXT J:NEXT 319 FOR I=1 TO X:FOR J=l TO SO:LPRINT AS(I,J);:NEX? J:NEXT I:RETURN 320 LOCATE ?!,::PRINT STRINM(S0,32!: 330 LOCATE 25,2:PRINT STRINGS(50,32): 340 LOCATE 252:COLOR 0,‘I:PRINT ” El Ese “;:LOCATE 25,ll 350 PRINT ” Cl CHRt 360 GI=INKEYI:IF G$=“” THEN 3bO 370 IF Gs=“E” THEN 60SUB 420:SOTO 400 380 IF 65:“;” THEN SOSUB 530:GOT0 400 390 IF G+“Q” THEN GOT0 410 400 GOT0 360 410 RETURN

“::LOCATE 25,27:PRINT ” Rleturn “::COLOR 7,O

“;:LOCATE 25,21:PRINT ” 01 end conmand “t:COLOR 7,0:STI=“”

Y.l:GOTO 40

=l:BEEP:

- SO IF B(=CHR%(13) THEN AJ(X,Y)=BhLOCATE X,Y:PRINT ’ “:X=X+l:Y~l:LOCRTE X,Y:PRINT

IIRETURN

Putting Gemini to Work

420 1:O:LOCATE 23,4:PRINT “Esc “;

430 6%=fNKEYS:IF 61:“” THEN 430

440 IF WCHR$(l3) THEN 480

. .

450 PRINT 6s; 460 PRINT ” “;

47b s~(I)*6~lI~I+lr6Ot0 430

480 IF 112 THEN FOR Jli TO IID~~DI+S$(J~:NEXT JrSTWHRI(27)+SRiO)

+CHRI(VAL(Dt)1rDW”

490 IF I-2 THEN STWHRS(27J+SS(OI+CHR$WALWfl1 t 1 SO0 IF I*1 THEN StWHR1127)+S1(0) 510 LPRINT ST$iSTS*“‘:FOR J=l TO I:SS(J)~““:NEX? J:I*O 520 LOCATE 23,4:PRINT ” 530 LOCATE 23,2:PRINT “CHRI “;:STl=“” 540 G$~INKEYhIF SW” THEN 540 550 IF SS=CHRS(13) THEN 570 560 PRINT 6Q:STWTI+GS:60TO 540

570 LOCATE 23,2:PRINT ”

‘:LPRINT CHRSWAL(STO)::STC=““:RETURN

“; :RETURN

Figure 54. A simple program, written in BAStC, that serves as a rudimentary word processing program.

In Figure 5-4, a very simple word processing software program is presented, written in BASIC for the IBM-PC. This program leaves some room for improvement, but after all - it’s free. You might apply it to writing short letters or other simple documents. The display on your CRT monitor may not be anything to write

home about, but at least it gives you the capability of writing home! You may also find the use of the control codes is somewhat awkward, but this program has its own menus which will make it easier for you to remember the commands. The program provides three different menus which display your options and prompt you to select specific commands to guide you in your word process-

ing. After you have typed in the program and entered RUN followed by a carriage return, the first menu will appear at the bottom of the screen and the cursor should be at the top left corner.

Now you can type in your text and correct any errors you may make. Because of the simplicity of this program, it does have some limitations, which will vary for the different computers. If your computer is an IBM-PC, you can type in 23 lines at up to 80 characters per line. Some other computers may not have the capacity to accept this many characters, limiting the amount of text you can type. This program is also restricted in that errors can only be corrected on the present line. Once you have hit <return > you can-

not go back to the previous line to revise it.

Gemini User’s Manual

After typing your text, you may go either to the second menu, which will permit you to print your text, or to the third menu where you may send Escape or control codes to the printer for special characters or effects. It is not necessary to type the entire ASCII codes. Instead, you have the option of selecting “ESC” or “CHR$“.

For example, if you wish to send CHR$(27); “W”; CHR!$(l); to the printer for printing of wide characters, you simply need to seiect the “ESC” option and type “Wl” and then hit c CR>, and the code will be sent to the printer. After sending the codes, you may gc back to the 2nd menu and print your text again.

The following is a listing of the commands:

CONTROL COMMANDS FOR THE “DO-IT-YOURSELF”

WORD PROCESSING PROGRAM (SHOWN IN FIGURE 5-4)

1st MENU

A P = gets you to the 2nd command level AD = deletes the character to the left of the cursor

AR = restart: clears the screen and lets you type a new text *E = exits the program

2nd MENU

P = prints your text

C = gets you to the 3rd command level

R = returns you to the 1st print level

3rd MENU

E(ESC) = lets you send ESC code with an abbreviated command C(CHR$) = lets you send a control code with an abbreviated

command

R = returns you to the 2nd level

These commands may vary if you are not using an IBM-PC, but the effects will be the same. For further explanation of the program variations, please refer to the computer-specific appendices at the

back of this manual.

6:’ /

Putting Gemini to Work

WHERE DO WE GO FROM HERE?

If you want to get to work, you may take your leave at this point.

You’ve gotten a good idea of what Gemini is all about - how the

parts fit together, how to add paper and ribbon, the Self-Test, interfacing with your computer, and various printing capabilities.

That should be enough to get you started.

To paraphrase an old saying: “A journey of a thousand pages

begins with a single character.” Bon Voyage!

If you have the luxury of enough time to keep reading, the next five chapters and accompanying appendices will provide you with the means to be able to travel first class. If knowledge is power, then you’ll be a powerful Gemini user by the end of this manual.

Understanding dot-matrix printing and Gemini’s graphics begins with knowing some details about the print head and the software that controls it. This chapter will provide you with those details. The print head, print matrix, and vertical spacing are described in understandable terms. The second half of this chapter will introduce you to dot graphics: the control codes for firing the “pins:’ and a sample graphics program that will put a smile on your

paper, and perhaps on your face.

THE PRINT HEAD

The print head contains nine thin wires, or pins, positioned one above the other. Figure 6-1 illustrates the print head, from the

paper’s point of view, looking straight on. Each wire is connected to a solenoid “gun;’ an electromagnet that “fires” when told to do so by the “computer” inside Gemini. Figure 6-2 presents a schematic of the print-head mechanism, profiling the solenoid, spring, and dot-wire pin for one of the guns.

THE FUNDAMENTALS OF

DOT MATRIX PRINTING

7-bit interface

O-bit Interface

Upw

Lower

Needle of

print head

B==

Figure 6-1. The bit-image column-scan capability is the result of nine pins, stacked in a column, each “fired” independently in response to signals from the 7-bit or a-bit interface from your computer.

“Needle” pin

Sprlng

Gemini User’s Manual

Paper

Platen

Pln gulde

$- Iron core

Clapper

Figure 6-2. This side-view schematic of the print-head mechanism shows

how electrical signals to the solenoid cause the clapper to “fire” the

needle-like pin that impacts the ribbon/paper/p/a ten. After the solenoid releases the clapper, a spring returns the pin to its original position.

instructions sent by your computer and directs the print head to discharge the correct pins in the proper order. The result of this “hiring” and “firing” is the printed characters produced by Gemini _ onto your paper.

letter “H” (see Figure6-3). Because the print head is bidirectional (can print right to left, and left to right), Gemini can start the “H” from either side.

one side of the letter. Then, the print head moves across the paper, and pin number four fires three times to create the horizontal line. Finally, the top seven pins fire simultaneously again to complete

the othervertical line. Aside from the amazing fact that the entire

printing operation just described can take place in approximately one-hundred and twentyth of a second, all this activity is

caused by a single ASCII code signal.

\’

Printer solenoid

Gemini’s built-in “computer” reads the ASCII code

Consider, if you will, the process of printing an uppercase

In this example, the top seven pins fire simultaneously to print

Bobbin

‘IL

Ribbon guide

Fundamentals of Dot Matrix Printkg

Figure 6-3. The nine rows of the matrix correspond to the nine pins on the

print head. For this uppercase letter, only the top seven pins fire - all at once

for each vertical line in this letter, and a single pin (firing repeatedly as the print head moves sideways) for the horizontal line.

This printing technology is called impact, dot matrix printing. Dots are printed according to a predesigned matrix or grid system. Each letter, numeral, punctuation mark, and other special character is formed by the arrangement of 4 to 36 dots.

The firing patterns for each character are pre-programmed in Gemini and stored in “firmware” (ROM’s). By sending the appropriate control codes to Gemini, we manipulate both the number of pins fired and the order in which they are fired. If you

know which control code to send from your computer’s keyboard,

through the computer to the printer, you can even create new

“characters” by controlling the firing pins.

THE PkNT MATRIX

Let’s turn to Appendix K and look briefly at the dot patterns of the various characters. All these characters, during the “normal” printing mode (standard and italic), are constructed within a !5dotwide by g-dot-high matrix of “boxes? All the dots are positioned vertically within one of the “boxes” in each column in the matrix.

Horizontally, the dots can be placed within any or all of the five boxes across the row or on the lines separating the boxes. If you thinkof the five boxes in a row as the “white” keys on a piano and the lines between them as four “black” keys, you can “play”

a dot in any of the nine dot positions across a row. Thus, even

Gemini User’s Manual

though there are only five boxes across, you have “9x9” printing

positions.

The uppercase letters are formed by the top seven pins. Some of the lowercase letters (“9:’ “j:’ “p:’ “q:’ and “y”) extend down to the eighth and ninth pins. This style of character generation, called

“true descenders:’ makes these letters much more readable.

The “underlining” character (ASCII code 95) is created by

firing only the ninth pin. The ESC CHR$(48) control code can also be used for underlining.

The block graphics characters (ASCII code numbers 224 through 255) are configured on a “6 x6” matrix. We’ll discuss these

characters a little later. A simple example of block graphics is shown in Figure 6-4: “W” “y” for the “Cowboy” state. (The BASIC program for producing Figure 6-4 is presented and discussed in

Chapter 7.)

Figure 6-4. Using block graphics and a simple program written in BASIC,

you can create very large type, as shown here.

Although the matrices are the same width, the dot configurations of the different characters in the alphanumeric and special symbol sets are different in their widths. The narrowest

letter is the lowercase “i” (ASCII code 105); the smallest character

is the fourdot period (ASCII code 46). The widest characters in the alphanumeric set are the uppercase letters, such as “M” (ASCII code 77).

When Gemini prints these characters, for example, during the first lines of the Self-Test, an extra “blank” column (a sixth column) is added to each character to provide spacing between them.

When you shift into the elite (12 CPI) or compressed mode

(17 CPI), the characters are the same height as in the normal mode,

but vary in width. With elite and compressed printing, the “columns” of the matrix become narrower.

fundamentals ot Dot Matrix Printing

With emphasized type, the matrix is 18 by 9 because each column is fired twice, horizontally offset by one-half dot on the second firing. Double-strike printing is accomplished by an 18 by 18 matrix, with the second printing vertically and horizontally offset by one-half dot. Emphasized plus double-strike is a 36 by 27 matrix, with the additional printings offset both horizontally and vertically.

In the double-width (“expanded”) mode, a column is printed, the print head moves over and repeats the same column configuration, then the print head moves over to twice-print the next column.

Superscripts and subscripts follow the same matrix pattern as the standard characters, but the print size of the matrix is onehalf as high.

b”.

L..

t..

cr..

k.“.

L..

11.

VERTICAL SPACING

On most conventional typewriters, you have a choice of single,

space-and-a-half, or double spacing. Your Gemini can print lines that are set to one-sixth inch, or one-eighth, or whatever spacing you want in increments as small as 11144th of an inch!

When you “initialize” your printer, Gemini is automatically set to avertical spacing of one-sixth inch if DIP Switch l-5 is “on” or one-eighth inch if DIP Switch l-5 is “off? One-sixth inch spacing,

which delivers six lines per inch, is the same as a standard “pica” typewriter, and is fine for text printing.

For block graphics (each of which is up to six dots tall), different spacing is required (or else your graphic “blocks” won’t fit together tightly).

Anticipating that you would want to be able to adjust the vertical spacing, Gemini provides you with the following five ways to make adjustments:

Software

Code

ESC “2” ESC “0” 118 ESC “1” 7172 ESC “A”n n/72 ESC “3” n

Height

(Inches)

116

n/l 44

Vertical

Dots

9 7

n/2

Geminl User’s Manual

As if that weren’t enough, there’s ESC “J” n, which does the same work as ESC “3” n but doesn’t change the value for successive line feeds.

Because each “dot” is l/72-inch in diameter, you have vertical spacing control as miniscule as half the thickness of a dot! Another way of expressing the same idea is that Gemini provides a high-resolution graphics pattern of 144 dots per vertical inch. With Gemini’s ultra-high horizontal resolution capability of 240 dots per inch, that makes for a powerful graphics tool, no matter how you look at it.

In Figure 6-5, you’ll see 1/144th-inch resolution, as well as the appearance of other “leadings” (pronounced “leddings”). Leading or line spacing is the amount of space set between lines of type.

Figure 6-5 presents sample leadings of 1/144th inch to approximately 115th inch. If you want to run the sample program that produces Figure 6-5, it is presented in BASIC. If you want to run this program, the following paragraphs discuss the “what’s and “why’s:’

A Sample Program that Demonstrates Vertical Spacing

The program presented in Figure 6-5b is short but takes awhile to

print. In the program, the first line prints a heading, a built-in title for your graphics. Line 20 starts a loop from 1 to 30: This loop controls the vertical spacing.

Line 30 may look strange, but it reveals an important part of

the limitations of BASIC. Although the language is easy to use,

it has a few quirks. In this case, a CHR$ code is intercepted by BASIC and used as a BASIC control code that is then sent to the

printer.

CHR$(13) is a code for a carriage return. Microsoft BASIC can’t resist inserting a line feed, CHR$(lO), behind every CHR$(13) that it handles en route to the printer. The computer language doesn’t know that this particular CHR$(lO) is the final character

in the ESC “3” n command that tells Gemini to change the

“leading” (line feed) to 13/144ths inch. There are ways to get around the problems (using the POKE statement, for example). For this program, we will bypass the problem and go to line 110 when the loop counter (I) equals 13.

Fundamentals of Dot Matrix Printing

Line 40 reveals that the variable M is used to control the number of times line 90 is executed. When I is small, M is large. When I is greater than 12, M is fixed to 2. Line 50 sets the vertical line spacing (you may recall that ESC = CHR$(27), “3” =

CHR$(Sl)). So, in this program, line 50 sets the vertical spacing to

11144 inches.

Line 60 starts a loop that uses the value of M to count 25 times when I equals 1, and counts 3 times when I is greater than 12. Line 70 prints a message telling us the value of the line spacing on the next-to-last line of the M loop. Line 80 spaces over the printing done by line 90 to column 30 by using the BASIC TAB statement.

Line 90 is where the action is. This line is similar to line 140

in the first reference program and prints 40 characters; its ASCII code is 241. This character is a six-dot straight line that is part of the block graphics set.

Line 100 and 110 end the J loops, and line 120 resets the

printer and ends the program.

Discussion of the Vertical Spacing Program

Let’s start by looking at how close the dots are vertically in Figure 6-5. Remember that the normal characters are seven dots high, which is 141144ths (7/72nds) of an inch. Therefore, if you wanted to print text, say in all uppercase letters, with each line resting atop the next, you’d set the vertical spacing at 14/144th of an inch.

When we use block graphics (where each block is 6 dot-

spaced high), we set the vertical spacing to 6/72 (or 12/144) inches.

The maximum value of n allowed for the vertical spacing

control code is 127. The result is that almost one inch (127/144ths)

for the ESC “3” n code, and roughly l-314 inches (127/72nds) for ESC “A” n.

In the sample program, we stopped I at 30, so the printout would fit on a standard 66-line sheet of sprocket-fed paper. If you wish to, you can replace the loop limit on line 20 with 127, and run the program again. You might also try replacing the CHRS(51) with CHR$(65) on line 50 and run the program using the n/72-inch vertical line spacing mode.

GeminiUser'sManual

High-Resolution Vertical Spacing Using the ESC 3 n Control Code

11144 21144

31144 41144

51144

61144

71144 81144 91144

101144 111144 121144

141144 151144

161144

171144

181144

191144

-- -

--- -_I--

--__I-

--I_ ---

---

-------

-------1------------

------- -------

-------------

---..--

--I -

201144

---------

----------

m---1_

---

211144

221144

----m-m- -------- ------em

------__--_--------I-

Figure 6-5a. This printout (actual size) shows the vertical spacing that you can control using the ESC 3 n code. This printout was created using the BASIC program shown at the bottom of Figure 6-5b (a continuation of this figure).

Fundamentals of Dot Matrix Printing

Inch

Spaclng

231144

241144

_------------------------------------

_----e--------m- 1--e------------p

-----------------------------~

----__---------

----------_---_---_^______ --

--a-----

25/l 44

261144

------ ---

27/l 44

--- -----m-----------w

---- ~~~~ ----I------_I_

-v----m

28/l 44

---

i0 LPRINT TAB(30);“High Resolution Vertical Spacing *

----

15 LPRINT TbB(30)~“Using the ESC 3 n Control Cod@ ” 20 FOR I * I TO 30 SO IF I = 13 THEN 6020 110 40 M * INT ( 144 I ( 6 t I 1 1 : !F II { 2 THEN H = 2 50 LPRINT CHR1(271; CHRt(Sll;CHRS(Il: 60 FOR J = 0 TO M 70 IF J = t-1 THEN LPRINT I : “/144 INCH SPACINS”; 80 LPRINT TRB(30)i 90 FOR N * 1 TO 401 tPRINT CHR$(2411; : NEXT N: LPRINT

100 NEXT J

110 NEXT I

120 LPRINT CHR$(27);“@“: END

--_

Figure 6-5b. This continuation of Figure 6-5a depicts a more “open” spacing, that you might use for prin ting drafts of documents that need room for letting the reviewer manually insert changes. This printout was produced by the BASIC program listed above, written for the IBM-PC. Consult the appendices to learn how to adapt this program to other computers.

INTRODUCTION TO DOT GRAPHICS

When we enter into the bit-graphics mode, we have complete

control over the firing of each individual pin in the print head. The graphics mode opens up the full potential of the Gemini printer by allowing us to create any image we can imagine. When printing dot graphics, Gemini can produce an ultra-high-resolution image (at 240 x 144) of over thirty thousand dots per square inch!

There are 80 characters, for example, in an 8inch-wide line

of text set in 10 CPI. For the same line width, you can print 136 -

condensed-width (17 CPI). As a point of comparison, you could fire up to 480 dots per line (that’s 60 dots per linear inch) in the “low” resolution graphics mode. In the ultra “high” resolution graphics mode, you could print graphic images with a precision of 1920dots per line (four times the number of “firings” per line-inch as in “low” resolution). “Dot’s” a lot of dots.

Fortunately, we don’t have to fill all the columns on every line, any more than a painter must apply all available paints to a single canvas.

After telling the printer to enter the graphics mode, we then define how many columns of dots we want to print in a line. We can send Gemini a string of instructions that tell which dots we want to fire in each column. A line-feed command can be used to conclude the graphics command sequence. We can repeat the graphic-mode commands, if that’s the goal, to repeat the graphic mode commands over and over or to fill an entire page with dot

image graphics.

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Graphic Control Codes

The low-resolution graphics mode is entered by sending Gemini a four-character control code:

ESC “K” nln2 where, ESC is the character represented by ASCII

“K” is the character for ASCII code

code CH R$(27) CHR$(75), which signals Gemini to put

low resolution into effect.

F undamenta/s of Dot Matrix Printing

Note: If we used ‘I” or CHR$(76)

instead of “K:’ we would be asking

Gemini for high-resolution graphics.

If we used “y” or CHR$(121), we would be asking for high-resolution graphics with double speed, and if we used “2” or CHR$(122), we would be asking for ultra-high-resolution graphics at normal speed.

nl and n2 represent the set of ASCII

codes that define how many columns of graphics to print on a line. If you want to print “x” number of columns of graphics on a line, then:

nl is the remainder of x/256, and n2 is the quotient of x/256

Note: For those of you who are

computer-wise and curious:

nl = x MODULO 256, and n2 = INTEGER of xl256

What does all this mean to the rest of us? The following table

might help.

If the number of columns,x,

ranges from:

1 to 255 256to 511 512 to 767 768 to 1023

1024 to 1279 1280 to 1535 1536 to 1791 1792 to 1920

then,

nl Is

x-x256 x- 512

x- 768

1024

X-

x - 1280 x - 1536 x-1792

then

n2 is

2 3 4 5 6 7

Remember: Gemini-70X can only print up to 480 columns in

low-resolution mode, 960 columns in high-resolution mode, and

1920 columns in ultra-high-resolution mode. The Gemini-15Xcan print 816 columns in low resolution, 1632 in high-resolution, and 3264 in ultra-high-resolution.

Gemini User’s Manual

Gemini requires that precisely the correct number of characters you specify with nl and n2 will follow immediately after the n2 control code. If there are too many (or too few) characters, unexpected and crazy things will happen.

The high-resolution graphics mode is entered by sending Gemini

the control code:

ESC “L” nln2, which selects the 120 dots-

per-inch column scan bit image

graphics mode. But Gemini’s graphics capabilities don’t stop there. The Gemini10X/15X, with control codes ESC “y” nln2 and ESC “z” nln2, will

take you two steps beyond high-resolution graphics, and allow you

to print faster and with even greater density.

ESC “y” nln2 commands the printer to

print dual-density graphics with

double-speed. In other words, your

result will be high-resolution graphics (as if you had used ESC ‘IL”) but they will be printed twice as fast!

ESC “z” nln2 puts Gemini in the quadruple-

density graphics mode (even more

dots per inch). The result of this ultra-

high-resolution mode is the capacity

to print 1,920 dots in one line on the

Gemini-lox, and 3264 dots in one

line on the Gemini-15X. (See the explanation of nl and n2 for ESC “K” to define how many columns of dots you want to print in a line.)

Firing the Pins

There are nine pins in the Gemini print head. In the graphics mode, you can control the upper eight. For those of you with computers that can only send seven bits (Apple II and some others), you control the top seven pins. Let’s look at the print head again and

label the pins as follows:

Fundamentals of Dot Matrix Pfinting

Print Head

Pin Number

Print Head &Bit

(toIN

7 .

Interface

128

64 64 32 32 16 18

not used

8 8 4 4 2 2

7.Bit

Interface

ns: used

not used

Based on the chart presented above, if you had a 7-bit computer and wanted to fire pins number 1 and 4 simultaneously, you would send CHR$(64+8). In other words, you’d send CHR$(72): Therein is the pattern. Thus, if you wanted to fire all the pins, using an 8-bit computer, you’d send:

CHR!$(128 + 64 + 32 + 16 + 8 + 4 + 2 + 1) = CHR$(255)

Control

Code

CHR$(128) CHR$( 64) CHR$( 32) CHR$( 16)

CHR$( 8) CHRS( 4) CHR$( 2) CHR$( 1)

CHR$( 0)

CHR$(255) CHR$( 72)

Binary

Representation

10000000

01000000

00100000

00010000 00001000 00000100

00000010

00000001

00000000

1 1 1 1 1 1 1 1

01001000

Fired

#l #2 #3 #4 #5 #6 #7 #8

none

all 8

Gemini User’s Manual

You computer aficionados may have already figured out that

the high-order bit of the character controls the top pin, the next

bit controls the number-two pin, etc.

Okay, now that you know how to fire the pins, what code do

you think will fire pins no. 5,6, and 8 with an 8-bit interface (per

the above chart)? How about CHR$ (8+4+1), or CHR$(13)? That may seem like a good answer, but (in the words of Hamlet) ‘lay, there’s the rub:’

CHR$(13) causes BASIC to automatically insert a line feed,

CHR$(lO), behind it. These BASIC programs were written several

years ago, before Gemini came along. Gemini is smart enough to

use CHR$(13) for a purpose other than initiating a carriage return; if only BASIC were as smart.

One solution to the above problem is to design your graphics programs so that they only use pins numbers 1 through 7 for 8-bit computers, and numbers 1 through 6 for 7-bit. Because the bottommost pin that normally can be used is fired by CHR$(l), all commands for the other usable pins will be even-numbered

(whatever their combination of numbers to fire whatever

combination of pins). With all the codes even-numbered, there’s no need to concern ourselves about unlucky old CHR!$(13). You might want to think about it for a while. There are other ways around the problem, but the even-number approach works (even if there seems to be something odd about it).

Example Graphics Program

Now that we’ve learned how to send the graphics controls to

Gemini, let’s construct a simple character to test low-resolution

printing. This program will show you one approach to creating graphic images. In the next chapter, we’ll consider more advanced techniques.

The first step in generating a sample program is to decide where to position the dots. One way is to start with a pencil and a piece of paper, especially paper with square grids printed on it. We will imagine that one dot will cover one square.

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