IOtech serial488a schematic

Serial488A, Serial488A/OEM, Serial488A/512K

User’s Manual

IOtech, Inc.

25971 Cannon Road

Cleveland, OH 44146

Phone: [phone]

Fax: [phone]

E-mail: [e-mail]

Internet: http://www.iotech.com

Serial488A, Serial488A/OEM,

Serial488/512K User’s Manual

p/n

SERIAL488/A-901, Rev 2.3

© 1998 by IOtech, Inc. — Printed in the United States of America

Warranty

Your IOtech warranty is as stated on the product warranty card. You may contact IOtech by
phone, fax machine, or e-mail in regard to warranty-related issues.
Phone: [phone], fax: [phone], email:

[e-mail]

Limitation of Liability

IOtech, Inc. cannot be held liable for any damages resulting from the use or misuse of this
product.

Copyright, Trademark, and Licensing Notic e

All IOtech documentation, software, and hardware are copyright with all rights reserved. No
part of this product may be copied, reproduced or transmitted by any mechanical,
photographic, electronic, or other method without IOtech’s prior written consent. IOtech
product names are trademarked; other product names, as applicable, are trademarks of their
respective holders. All supplied IOtech software (including miscellaneous support files,
drivers, and sample programs) may only be used on one installation. You may make archival
backup copies.

FCC Statement

IOtech devices emit radio frequency energy in levels compliant with Federal Communications
Commission rules (Part 15) for Class A devices. If necessary, refer to the FCC booklet How To Identify
and Resolve Radio-TV Interference Problems (stock # 004-000-00345-4) which is available from the
U.S. Government Printing Office, Washington, D.C. 20402.

CE Notice

Many IOtech products carry the CE marker indicating they comply with the safety and emissions
standards of the European Community. As applicable, we ship these products with a Declaration of
Conformity stating which specifications and operating conditions apply.

Warnings and Cautions

Refer all service to qualified personnel. This caution symbol warns of possible personal injury or
equipment damage under noted conditions. Follow all safety standards of professional practice and the
recommendations in this manual. Using this equipment in ways other than described in this manual can
present serious safety hazards or cause equipment damage.

This warning symbol is used in this manual or on the equipment to warn of possible injury or death from
electrical shock under noted conditions.

This ESD caution symbol urges proper handling of equipment or components sensitive to damage from
electrostatic discharge. Proper handling guidelines include the use of grounded anti-static mats and wrist
straps, ESD-protective bags and cartons, and related procedures.

Specifications and Calibration

Specifications are subject to change without notice. Significant changes will be
addressed in an addendum or revision to the manual.

hardware products to published specifications. Periodic hardware calibration is not covered
under the warranty and must be performed by qualified personnel as specified in this manual.
Improper calibration procedures may void the warranty.

As applicable, IOtech calibrates its

Quality Notice

IOtech has maintained ISO 9001 certification since 1996. Prior to shipment, we thoroughly test our
products and review our documentation to assure the highest quality in all aspects. In a spirit of
continuous improvement, IOtech welcomes your suggestions.

Introduction

1.1 Description

The

Serial488A, Serial488A/OEM

provide transparent communication from a serial computer to an IEEE 488 printer,
plotter or other device. They also can be used to control a serial device, such as a
printer or terminal, from an IEEE 488 host computer.

As a serial to IEEE 488 converter, it receives data from a serial host then
automatically performs the bus seq uences necessary to send this data to t he IEEE 488
device. If desired, data can be requested from the IEEE 488 device and returned to the
host.

As an IEEE 488 to serial converter, it functions as a peripheral to an IEEE 488
controller. Data received from the controller is sent to the serial device, and data
received from the serial device is buffered for transmission to the IEEE 488 controller.
The converter can inform the host, by the serial poll status byte, that it has received
data from the serial device.

The

Serial488A

422 devices by positioning configuration jumpers located within the unit. Both
devices can communicate at selectable baud rates up to 57600 baud.

and

Serial488A/OEM

and

Serial488/512K

can communicate with RS-232 and RS-

Bus Converters

The

Serial488/512K

rates up to 19200 baud.

This manual will refer to all three interfaces as the
between the
applicable.

Serial488A, Serial488A/OEM

can communicate with RS-232 devices at selectable baud

. Differences

and

Serial488/512K

Serial488A

will be noted where

1.1

1.2 Serial488 and Serial488A Differences

The

Serial488A

is both a hardware and firmware upgrade to the

Serial488

When issuing product improvements, we try to maintain transparent compatibility.
Occasionally this is not possible. You should note the following differences between
the two products.

1. The

Serial488

characters. The

allocated fixed serial and IEEE input buffers of 4000

Serial488A

utilizes a 32,000 character buffer which is
dynamically allocated to the serial and IEEE input buffers as required.
Refer to Section 4.2 for more details

2. The

Serial488A

has the ability to output RS-232 or RS-422 levels. The

levels used are internally selectable. Refer to Section 2.8 for details.

3. As a peripheral, the

Serial488A

's serial poll status byte has been
changed to include status of the serial handshake. Other minor changes
have also been included. Refer to Section 4.4 for a complete description
of the serial poll status byte.

4. The internal switch settings for baud rate have been adjusted to include
57600 baud. Refer to Section 2.3 for the new switch settings.

.

1.3 Serial488A, Serial488A/OEM and Serial488/512K Differences

1. The

Serial488A

and

Serial488A/OEM

utilize a 32,000 character buffer

which is dynamically allocated to the serial and IEEE input buffers as required. The

Serial488/512K

utilizes a 512,000 character buffer which is dynamically allocated to

the serial and IEEE input buffers as required.

2. The

RS-422 levels. The

3. The

Serial488A

Serial488/512K

Serial488A

up to 57600 baud. The

and

Serial488A/OEM

can only operate at RS-232 levels.

and

Serial488A/OEM

Serial488/512K

have the ability to output RS-232 or

can operate at selectable baud rates

can operate at selectable baud rates up to

19200 baud.

1.2

1.4 Available Accessories

Additional accessories that can be ordered for the

CA-7-1
CA-7-2
CA-7-3
CA-7-4
CA-11
CA-21
CA-22
CA-23
CN-20
CN-22
CN-23
ABC488
Rack488-3
Rack488-4
140-0920

Serial488A

include:

1.5 foot IEEE 488 Cable
6 foot IEEE 488 Cable
6 foot shielded IEEE 488 Cable
6 foot reverse entry IEEE 488 Cable
12 foot IBM PC/XT/PS2 to Serial488A RS-232 Cable
12 foot Macintosh II/SE/Plus to Serial488A RS-232 Cable
12 foot Macintosh 512K to Serial488A RS-232 Cable
12 foot IBM AT to Serial488A RS-232 Cable
Right Angle IEEE 488 adapter, male and female
IEEE 488 Multi-tap bus strip, four female connectors in parallel
IEEE 488 panel mount feed-through connector, male and female
IEEE 488 ABC switch
5-1/4" by 19" rack mount for one
5-1/4" by 19" rack mount for two

Serial488A

Serial488A

s

Instruction Manual

1.3

Specifications

Do not use this interface outdoors! The interface is intended for indoor use only! Outdoor
conditions could result in equipment failure, bodily injury or death!

If equipment is used in any manner not specified in this manual, the protection provided by the
equipment may be impaired. Please read this manual carefully.

Do not connect AC line power directly to the Serial488A. Direct AC connection will damage the
equipment.

Serial488A

:$51,1*

:$51,1*

&$87,21

IEEE 488

&$87,21

The IEEE 488 terminal must only be used to control a non-isolated IEEE 488 system. The
common mode voltage (cable shell to earth) must be zero.

Terminal Installation Category:

Standard: Not Applicable CE: Category 1

Implementation: C1, C2, C3, C4 and C28 controller subsets.(Serial to IEEE)

SH1, AH1, T6, TE0, L4, LE0, SR1, RL0, PP0, DC1, DT0, E1.
Terminators: Selectable CR, LF, LF-CR and CR-LF with EOI.
Connector: Standard IEEE 488 connector with metric studs.

Serial Interface

Terminal Installation Category:

Standard: Not Applicable CE: Category 1
EIA RS-232C: AB, BA, BB, CA, CB
EIA RS-422A: Balanced voltage on TxD and RxD.
Character Set: Asynchronous bit serial.
Output Voltage: ±5 volts min (RS-422A). 5 volts typical (RS-232C).
Input Voltage: ±3 volts min.; ±15v max.
Baud Rate: Selectable 110, 300, 600, 1200, 1800, 2400, 3600, 4800, 7200,

9600, 19,200 and 57,600.

1.4

Data Format: Selectable 7 or 8 data bits; 1 or 2 stop bits; odd, even, mark,

space and no parity on transmit.
Duplex: Full with Echo/No Echo.
Serial Control: Selectable CTS/RTS or XON/XOFF.
Terminators: Selectable CR, LF, LF-CR and CR-LF.
Connector: 25-pin Sub-D male. DCE Configured.

General

Terminal Installation Category:

Standard: Not Applicable

CE: Category 1 for all terminals.
Data Buffer: 32,000 characters dynamically allocated.
Indicators: LEDs for IEEE Talk and Listen, Serial Send and Receive, and

Power.

Power: An external power supply is provided with the Serial488A.

Input is 105 to 125VAC; 50 to 60 Hz, 10 VA Maximum.

Dimensions: 188mm deep x 140mm wide x 68mm high (7.39" x 5.5" x

2.68").

Weight: 1.55 kg. (3.6 lbs).

Operating Environment:

Standard: Indoor use, 0° to 50°C; 0 to 70% R.H. to 35°C.

Linearly derate 3% R.H./°C from 35° to 50°C.

CE: Indoor use at altitudes below 2000m, 0° to 40°C; 80% maximum

RH up to 31°C decreasing linearly 4% RH/°C to 40°C.

Controls: Power Switch (external), IEEE and Serial parameter switches

(internal). Jumper selection of RS-232 or RS-422 operation
(internal).

*Specifications subject to change without notice

1.5

.

Serial488A/OEM

IEEE 488

Implementation: C1, C2, C3, C4 and C28 controller subsets.(Serial to IEEE)

SH1, AH1, T6, TE0, L4, LE0, SR1, RL0, PP0, DC1, DT0, E1.
Terminators: Selectable CR, LF, LF-CR and CR-LF with EOI.
Connector: Standard IEEE 488 connector with metric studs.

Serial Interface

EIA RS-232C: AB, BA, BB, CA, CB
EIA RS-422A: Balanced voltage on TxD and RxD.
Character Set: Asynchronous bit serial.
Output Voltage: ±5 volts min (RS-422A). 5 volts typical (RS-232C).
Input Voltage: ±3 volts min.; ±15v max.
Baud Rate: Selectable 110, 300, 600, 1200, 1800, 2400, 3600, 4800, 7200,

9600, 19,200 and 57,600.
Data Format: Selectable 7 or 8 data bits; 1 or 2 stop bits; odd, even, mark,

space and no parity on transmit.
Duplex: Full with Echo/No Echo.
Serial Control: Selectable CTS/RTS or XON/XOFF.
Terminators: Selectable CR, LF, LF-CR and CR-LF.
Connector: 25-pin Sub-D male. DCE Configured.

General

Data Buffer: 32,000 characters dynamically allocated.
Indicators: LEDs for IEEE Talk and Listen, Serial Send and Receive, and

Power.
Power: User supplied +5 volts ±0.25% at 1 amp. Mating power

connector with 8 inch leads provided.
Dimensions: 205mm deep x 115mm wide x 28mm high (8" x 4.5" x 1.1").
Weight: 0.23kg. (0.5 lbs.)
Environment: 0° - 50°C; 0 to 70% R.H. to 35°C. Linearly derate

3% R.H./°C from 35° to 50°C.
Controls: IEEE and Serial parameter switches. Jumper selection of

RS-232 or RS-422 operation.

*Specifications subject to change without notice

.

1.6

Serial488/512K

IEEE 488-1978

Implementation: C1, C2, C3, C4 and C28 controller subsets.(Serial to IEEE)

SH1, AH1, T6, TE0, L4, LE0, SR1, RL0, PP0, DC1, DT0, E1.
Terminators: Selectable CR, LF, LF-CR and CR-LF with EOI.
Connector: Standard IEEE 488 connector with metric studs.

Serial Interface.

EIA RS-232C: AB, BA, BB, CA, CB
Character Set: Asynchronous bit serial.
Output Voltage: 5 volts typical (RS-232C).
Input Voltage: ±3 volts min.; ±15v max.
Baud Rate: Selectable 110, 300, 600, 1200, 1800, 2400, 3600, 4800, 7200,

9600, and 19,200.
Data Format: Selectable 7 or 8 data bits; 1 or 2 stop bits; odd, even, mark,

space and no parity on transmit.
Duplex: Full with Echo/No Echo.
Serial Control: Selectable CTS/RTS or XON/XOFF.
Terminators: Selectable CR, LF, LF-CR and CR-LF.
Connector: 25-pin Sub-D male. DCE Configured.

General

Data Buffer: 512,000 characters.
Indicators: LEDs for IEEE Talk and Listen, Serial Send and Receive, and

Power.
Power: 105-125V or 210-250V; 50-60 Hz, 10 VA Max.
Dimensions: 188mm deep x 140mm wide x 68mm high (7.39" x 5.5" x

2.68").
Weight: 1.95 kg. (4.35 lbs).
Environment: 0° - 50°C; 0 to 70% R.H. to 35°C. Linearly derate

3% R.H./°C from 35° to 50°C.

Controls: Power Sw itch (external)

IEEE and Serial parameter switches (internal).

*Specifications subject to change without notice

.

1.7

1.6 Abbreviations

The following IEEE 488 abbreviations are used throughout this manual.
addr n IEEE bus address "n"

ATN Attention line
CA Controller Active
CO Controller
CR Carriage Return
data Data String
DCL Device Clear
GET Group Execute Trigger
GTL Go To Local
LA Listener Active
LAG Listen Address Group
LF Line Feed
LLO Local Lock Out
MLA My Listen Address
MTA My Talk Address
PE Peripheral
PPC Parallel Poll Configure
PPU Parallel Poll Unconfigure
SC System Controller
SDC Selected Device Clear
SPD Serial Poll Disable
SPE Serial Poll Enable
SRQ Service Request
TA Talker Active
TAD Talker Address
TCT Take Control
term Terminator
UNL Unlisten
UNT Untalk
* Unasserted

1.8

Getting Started

2.1 Inspection

The

Serial488A

prior to shipment. When you receive the interface, carefully unpack all items from the
shipping carton and check for any obvious signs of physical damage which may have
occurred during shipment. Immediately report any such damage found to the shipping
agent. Remember to retain all shipping materials in the event that shipment back to
the factory becomes necessary.

Every

Every

Serial488A

•

Serial488A

•

140-0920

•

Power Supply

Serial488A/OEM

was carefully inspected, both mechanically and electrically,

is shipped with the following....

IEEE 488 Bus Converter
Instruction Manual
9 Volt Regulated
TR-2; 115V or
TR-2E; 220V

is shipped with the following....

Every

•

Serial488A/OEM

•

140-0920

Serial488/512K

•

Serial488/512K

•

140-0920

•

Power Supply

IEEE 488 Bus Converter
Instruction Manual

is shipped with the following....

IEEE 488 Bus Converter
Instruction Manual
9 Volt Regulated
TR-2; 115V or
TR-2E; 220V

2.1

2.2 Configuration

Three DIP switches internal to the

Serial488A

set the configuration of the
interface. NOTE: Selectable functions are read ONLY at power-on and should only
be set prior to applying power to the interface. The following figures illustrate the
factory default settings which are:

Serial Port: IEEE:

9600 Baud Mode = IEEE 488 Controller
8 Data Bits Address = 10
2 Stop Bits Bus Terminator = LF; EOI Disabled
No Parity Talk-back on Terminator Enabled
Serial Terminator = LF Talk-back on Time Out Enabled
Echo Disabled
RTS/CTS Handshake

SW3 Factory Default Settings

IEEE Addr

IEEE Term

EOI

12345678

SW3

OPEN

10
LF
Disabled

Switch

DOT

Side
View

2.2

SW2 Factory Default Settings

Mode

Talk Back on Time Out

Serial Term

Echo

Parity

Handshake

Word Length

Talk Back on Term

12345678

SW2

OPEN

C

Enabled

LF
No Echo
No Parity

SW1 Factory Default Settings

12345678

Baud Rate

Stop Bits

SW1

9600
RTS/CTS
8 Data Bits
Enabled
2 Stop Bits

OPEN

Switch

DOT

Side
View

DOT

Switch

Side
View

The following drawings show the locations of switches SW1, SW2, and SW3 for

the

Serial488A, Serial488A/OEM

the

Serial488A

and the

Serial488/512K

and the

Serial488/512K

is referred to as the I/O board.

2.3

. The top circuit board in

Serial488A Switch Location - I/O Board

12345678

OPEN

12345678

OPEN

12345678

S203

SW2 SW3

S202

SW3

SW2

SW1

OPEN

S201

Serial488A/OEM Switch Location

S101

12345678

SW1

OPEN

SW-6-8

S102

12345678

SW2

OPEN

SW-6-8

S103

12345678

SW3

SW1

OPEN

SW-6-8

2.4

Serial488/512K SW1, SW2 Location - I/O Board

12345678

SW2

SW-6-8

12345678

OPEN

IC-39

74HCT244

C-5-.1

RN-1-10K

SW1

OPEN

SW-6-8

Serial488/512K SW3 Location - Motherboard

12345678

OPEN

SW3

S102

2.5

Note that the

the

Serial488A

Serial488A

is designed to allow an RS-232 computer to communicate with an

comes configured as an IEEE controller. In t his mod e

IEEE peripheral such as a plotter. This controller mode is described in detail in

Section 3

.

The

Serial488A

peripheral, the

Serial488A

device. The peripheral mode of operation is described in detail in

may also be configured as an IEEE peripheral. As an IEEE

allows an IEEE controller to commun icate with an RS-232

Section 4

.

To modify any of these defaults, follow this simple procedure: Disconnect the
power supply from the AC line and from the interface. Disconnect any IEEE or serial
cables prior to disassembly.

WARNING
Never open the Serial488A case while it is
connected to the AC line. Failure to observe this
warning may result in equipment failure,
personal injury or death.

Place the interface upside down on a flat surface. Remove the four (4) screws
located near the rubber feet. Return the interface to the upright position and carefully
remove the top cover. Modify those parameters which are appropriate for your
installation and then carefully re-assemble the interface using the reverse of the
procedure described.

2.3 Serial Port Settings

The first parameters to configure are those that correspond to the RS-232 port.
These include baud rate, word length, number of stop bits, parity selection and type of
RS-232 handshake. Each of these are described in the following sections.

2.3.1 Serial Baud Rate Selection

Baud rate defines the number of serial bits per second transferred into
and out of the RS-232 interface. SW1-1 through SW1-4 determine the
serial baud rate. The factory default baud rate is 9600 baud. Baud rates
may be selected from 110 to 57600 baud (110 to 19200 for the

Serial488/512K

).

2.6

Refer to the following diagram for specific baud rates. Note: on the

Serial488/512K

selecting 57600 baud will have the same effect as selecting 19200 baud.

SW1 View for Serial Baud Rate Selection

,

12345678

110 1800

OPEN

12345678

110 2400

OPEN

12345678

110 3600

OPEN

12345678

135 4800

OPEN

12345678

150 7200

OPEN

12345678

12345678

OPEN

12345678

OPEN

12345678

OPEN

12345678

OPEN

12345678

OPEN

12345678

Switch

Side
View

DOT

300 9600

OPEN

12345678

600 19200

OPEN

12345678

1200 57600

OPEN

OPEN

12345678

OPEN

12345678

OPEN

2.7

2.3.2 Serial Word Length Selection - Data Bits

SW1-6 determines the number of data bits, often referred to as word
length, for each serial character transmitted or received. The factory default
is 8 data bits.

SW1 View of Serial Word Length (Data Bits) Selection

12345678

OPEN

12345678

OPEN

Switch

Side
View

DOT

8 Data Bits 7 Data Bits

2.3.3 Serial Stop Bit Selection

Switch SW1-8 determines the number of stop bits contained in each
serial character transmitted and received. The factory default is 2 stop bits.

SW1 View for Serial Stop Bit Selection

12345678

OPEN

12345678

1 Stop Bit 2 Stop Bits

Switch

Side
View

OPEN

DOT

2.3.4 Serial Parity Selection

Serial Parity is selected with S2-6 through S2-8. The

Serial488A

generates the selected parity during serial transmissions but it does not
check parity on data that is received. The factory default is parity disabled.

2.8

SW2 View for Serial Parity Selection

12345678

OPEN

Odd Parity Mark Parity

12345678

OPEN

Even Parity Space Parity

12345678

Parity Disabled

2.3.5 Serial Echo Selection

12345678

OPEN

12345678

OPEN

OPEN

Switch

DOT

Side
View

Serial data sent to the

Serial488A

will be echoed back to the serial

host if SW2-5 is set to the open position. Factory default is Echo Disabled.

12345678

OPEN

Echo Disabled Echo Enabled

SW2 View for Echo Selection

12345678

OPEN

Switch

DOT

Side
View

2.9

2.3.6 Serial Handshake Selection

Switch SW1-5 is used to select between hardware [
software [

With

Xon/Xoff

Xon/Xoff

] serial handshake control.

, the

Serial488A

issues an

Xoff

RTS/CTS

character [ASCII value

] or

of $13] when its buffer memory is near full. When issued, there is greater
than 1000 character locations remaining to protect against buffer overrun.
When it is able to accept more information it issues an
[ASCII value of $11]. The

Serial488A

from the serial host it is communicating with.
becomes inactive when

Xon/Xoff

set to an active high state. The

is enabled. The

CTS

also accepts

Xon/Xoff

RTS/CTS

output is, however,

RTS

input is not used for this handshake

Xon

serial control

character

on transmit

and may be left floating (unconnected).

With

RTS/CTS

, the

Serial488A

un-asserts

(low) when its buffer

RTS

memory is near full. When un-asserted, there is greater than 1000 character
locations remaining to protect against buffer overrun. When it is able to
accept more information it asserts (high)
transmit data to the serial host if it detects the

RTS

CTS

. The

Serial488A

will not

input un-asserted (low)

when configured for this hardware handshake.

The factory default serial control is hardware,

SW1 View for Serial Handshake Selection

12345678

OPEN

RTS/CTS Xon/Xoff

12345678

OPEN

RTS/CTS

Switch

Side
View

.

DOT

2.10

2.4 Terminator Selection

The

Serial488A

can be configured to provide RS-232 to IEEE 488 and IEEE
488 to RS-232 terminator substitution. This is useful when interfacing an RS-232
device which only issues carriage return [CR] as an output terminator to an IEEE
controller which expects a carriage return followed by a line feed [CR-LF].

In the above example, the serial terminator should be selected for CR Only while
the IEEE terminator is set to CR-LF. When a serial CR character is received, it is
discarded and substituted with an IEEE CR-LF. In the IEEE to RS-232 direction, the
IEEE CR is unconditionally discarded. Upon receipt of the IEEE LF, a serial CR is
substituted.

The

Serial488A

can be made totally data transparent by setting both the serial

and IEEE terminators to be CR Only or LF Only.

2.4.1 Serial Terminator Selection

SW2-3 and SW2-4 select the serial terminators for the serial input and

output. The factory default is LF Only.

SW2 View for Serial Terminator Selection

12345678

OPEN

CR Only LF-CR

12345678

OPEN

LF Only CR-LF

12345678

OPEN

12345678

OPEN

Switch

DOT

Side
View

2.11

2.4.2 IEEE Bus Terminator Selection

SW3-6 through SW3-8 set the IEEE bus terminators used for data sent

or received by the

Serial488A

. EOI, a line used to signal the end of a
multiple character bus transfer, may also be enabled. If enabled, EOI is
asserted when the last selected bus terminator is sent. Factory default is LF
Only with EOI disabled.

SW3 View for IEEE Bus Terminator Selection

12345678

12345678

12345678

EOI Disabled EOI Enabled

2.5 Mode Selection

12345678

OPEN

OPEN

CR Only LF-CR

12345678

OPEN

OPEN

LF Only CR-LF

12345678

OPEN

OPEN

Switch

DOT

Side
View

SW2-1 sets the major operating mode of the

Serial488A.

The

IEEE Controller

(RS-232 to IEEE Converter) mode allows a serial host device to send data to a single
IEEE bus peripheral. Applications include interfacing a listen-only or addressable
IEEE printer/plotter to a serial printer port. Refer to

Section 3

for more detailed

information on the controller mode of operation.

2.12

The

Peripheral

controller. Data whi ch is sent b y the IEEE control ler to t he

mode is used when interfacing a serial device to an IEEE

Serial488A

is transmitted
out its serial port. Data received from the serial device is buffered by the
until read by the IEEE controller. Refer to

Section 4

for more detailed information on

the peripheral mode of operation.

Serial488A

The factory default is the

IEEE Controller

mode, an RS-232 to IEEE converter.

SW2 View for Mode Selection

12345678

OPEN

Controller Mode Peripheral Mode

12345678

OPEN

Switch

Side
View

DOT

2.6 IEEE Address Selection

SW3-1 through SW3-5 select the IEEE bus address of the

the

IEEE Peripheral

mode. These same switches are used in the

Serial488A

IEEE Controller

mode to select the address of the device that will be controlled. [Refer to

when in

Sections 4

and 3 respectively for additional information]. The address is selected by simple
binary weighting with SW3-1 being the least significant bit and SW3-5 the most
significant. The factory default is address 10.

Listen Only

the

Serial488A

is a special type of

Peripheral

accepts all data transmitted on the bus, ignoring any bus addressing,

and transfers it out its serial port. The

Serial488A

operation. In the

is set to

Listen Only

Listen Only

mode by

mode

setting its ad dress to 31. If the IEEE address is set to 31 in the pe ripheral mode, it is
adjusted to 30.

2.13

SW3 View for IEEE Address Selection

12345678

0
1

OPEN

0 x 16
1 x 8
0 x 4
1 x 2
0 x 1

+

Switch

Side
View

= 0
= 8
= 0
= 2
= 0

DOT

IEEE Address = 10

2.7 Feature Selections

The functions of the remaining switches are dependent on the mode selected. A
brief description of each of these features follows. You should refer to the listed
sections for additional information.

2.7.1 Controller Features

In the

IEEE Controller

(RS-232 to IEEE 488 Converter) mode, SW1­7 is used to determine whether the interface should, after sending the IEEE
bus terminators, address the attached bus device to talk. The factory default
is

Talk-back On Terminator

SW2-2 selects whether the
bus device to talk when the
device. The factory default is

Refer to

Section 3

for complete details on these features.

enabled.

Serial488A

Serial488A

should address the attached

has nothing more to send to that

Talk-back On Time Out

enabled.

2.14

SW1 View for Controller Talk-Back on Terminator Selection

12345678

OPEN

Talk Back on

Terminator Disabled

SW2 View for Controller Talk-Back on Time-Out Selection

12345678

OPEN

Talk Back on

Time Out Disabled

2.7.2 Peripheral Features

12345678

OPEN

Talk Back on

Terminator Enabled

12345678

OPEN

Talk Back on

Time Out Enabled

Switch

DOT

Side
View

DOT

Switch

Side
View

In the

IEEE Peripheral

enables the interface to assert the

(IEEE 488 to RS-232 converter) mode, SW1-7

IEEE bus interface line to indicate

SRQ

that it has received the last switch selected serial terminator character from
the serial device.

SW1 View for Peripheral SRQ on Last Serial Terminator

12345678

OPEN

SRQ on Last

Terminator Disabled

12345678

OPEN

SRQ on Last

Terminator Enabled

Switch

Side
View

DOT

2.15

2.8 Serial Interface

The

Serial488A

and

Serial488A/OEM

have the ability to output signal levels
that are compatible with either RS-232 or RS-422. An internal DIP shorting plug
determines which electrical specification is chosen. If the interface is to be connected
to an IBM PC/XT/AT/PS2 or compatible, the RS-232 level should be selected. If it
will be connected to a Macintosh 512K/Plus/SE/II, the RS-422 level should be used.
For connection to other computers, refer to the manufacturer's manual to determine
which levels are supported.

2.8.1 RS-232/RS-422 Signal Level Selection

The

Serial488A

's and

Serial488A/OEM

's factory default signal levels
are compatible with RS-232. To select RS-422 levels, carefully remove the
8 position shorting plug with a small flat blade screwdriver from it's socket.
Install the DIP jumper into the adjacent socket making certain that all of
the pins on the shorting plug are inserted correctly. The following diagrams
show which socket the jumper must be inserted for the desired operation.

RS-232 Signal Levels Selected - Serial488A

Shorting Plug

J205

RS-422 RS-232

J206

2.16