Epson C82302-04 Owner's Manual

EPSON

32KB
Serial Interface

INTRODUCTION

The Serial Interface C82302* / C82304* is an interface
board that allows asynchronous serial data communica­tion between a host computer and an Epson printer.

This board

a 32K byte buffer that frees up your computer for
other uses while your printer continues to print.

two self-test functions that can help solve interface

problems.

signal levels that can be set at either RS232C or 20

mA Current Loop.
handshaking protocol using X-on/X-off or DTR flag

control.
selectable data word structure. This

choose parity (Odd. Even, or None) and word bit

settings (either 7 or 8 bit).
selection of baud rate settings from 75 to 19,200 BPS.

(Data transmission speed is limited to 1,200 BPS
when the signal level is set to 20 mA Current Loop.)

This optional interface board is intended for use with the
following Epson printers:

FX, FX+, JX, LX, RX, RX+, HI-80 IX-800, EX-800/1000,

LQ-series (except for LQ-1500), SQ-series (except for SQ-

2000)

features:

allows you to

About this guide

This guide is designed to give you detailed information
on how to install your C82302* / C82304* serial interface

board

in a variety of Epson printers. Installation

procedures vary slightly depending upon the printer
model

that you have.

Also included, are instructions on how to adjust the

settings of the C82302*/C82304* interface board, as well

as a general description of serial data communication.

The C82302*/C82304* option package contains the
following items:

Optional connector loch nuts (2)

Note

When attaching the interface cable to the interface. you

nay find that the screws of your interface cable do not
it into the connector lock nuts. If this happens you will

need to replace the connector lock nuts with the optional

ones provided in this package.

2

SETTING THE CONDITIONS

The C82302*/C82304* interface board has two sets of

DIP (Dual In-line Package) switches, and 16 jumpers.

These switch& and jumpers are used for selecting
various interface operations.

Board layout

The figure below shows the layout of the C82302*/
C82304* board, and the locations of
and jumpers.

Figure 2. Board layout

the DIP switches

3

The c82302*/c82304* interface board has two sets of

DIP (Dual in-line Package) switches, and 16 jumpers.
These switches and jumpers are used for selecting
various interface operations.

Board layout

The figure below shows the layout of the (C82302*/

C82304* board, and the locations of the DIP switches
and jumpers.

Figure 1. Board layout

- - “7,

I

4

m1

4

~qJqhstalltheCgL302*/-~krfaa,you
nutyncedtoadjustsomeofthe=kings. Whennuking
DIp&t&Kttin
dtice,suchasa

CSUtiOll

chan~,itbbUttO~SpOinted

-point pen

fall

oramalllsawdljver.

All changes of DIP switch and jumper settings show are
made with the printer power turned off.
chacks and

recognizes new settings only at the time the

the printer

power is turned on
About DIP

switches

The two sets of DIP switches on the C82302*/C82304*
are labelled SW1and SW2. Each set contains a number
of individual toggIe type switches that can be set either
onoroff.
(SW1 or SW2) and number.

The individual switches are referred to by set

Therefore, the switch in set
SW1 marked by the small number 3 is calIed DIP switch
1-3

5

DIP switch 1(Interface operations)
The table below contains information on switch func-

tions, and the factory setting

of each

switch.

The

switches on DIP switch 1 allow you to change interface

functions.

Table

1- DIP

-------

L

s

l-1

l-2
l-3 Evcn/ald puity-

I4 potalityae~

lb

--

14

1-7

la

smitch 1

--.

ON OFF

WUdhI@h-

Parity check

Irksam

FLgtUIlUpaitivdnqative Negative

auble/diubk

Baudntelektion

7bth

Enable

Even Odd

@JoteZ) OJaal)

See Table 3.

(bib

OFF

I)iyMc

OFF

Paith’f!

1

‘z

OFF
m

OFF

OFF

OFF
OFF

Note

1. Positive:
Data Entry Enabled DTR ON (+3V to +27v)
Data Entry Disabled DTR OFF (-3V to -27V)

2 Negative:

Data Entry Enabled DTR OFF (-3V to -27W
Data Entry Disabled DTR ON (+3V to +27v)

6

Data word structure
The data word structure is also operator selectable

through DIP switch settings (see Table 1). The word
structure for serial data is:

1 start bit + 7 or 8 data bits (selectable) + 1 Even or
Odd parity bit (optional) + 1 or more stop bits

The table below shows the possible word

Combinations.

structure

Baud rate selection
In serial data communication, data is transmitted in the

form of bits. These data bits go out one at a time along a

(Bits

single path, and in a specified order. The BPS

Per

Second) rate, or speed at which these bits are transmit-

ted, can be selected using a combination of DIP switch

settings.
Note

In the current loop mode, normal data transfer operation
cannot be guaranteed at a baud rate setting exceeding

1,200 bps

7

the printer buffer is enabled. The buffer is a memory

which can temporarily store data from a computer.

Table 3. Band rate selection

Note
Switch combinations other than those shown above will
be taken as a setting for

8

Dip switch 2 (interface operations)

The table below contains information

on

switch func­tions, and the factory setting of each switch The
switches on DIP switch 2 allow you to change interface

functions and select the self test modes .

Note

This interface board operates when DIP switch 2-1 is

turned on. By turning this switch off, the parallel
interface of the printer can be used even with the serial
interface board installed. You should, however, remove
any unused interface cable to prevent the possibility of
radio frequency interference.

9

Buffer full recovery timing

When the available space for bytes in the print buffer

drops to 512 or 16 bytes, data entry is disabled. As the
printer prints the data in the buffer, the vacant area for

bytes increases. when this vacant area reaches one of

cation is resumed. These settings are selectable by using
the DIP switches.

The jumper is a small terminal used for connecting or

disconnecting a circuit. The jumper is on when the

jumper plug covers

both wires of the terminal. Jumper
settings can be changed by either attaching or removing
the rectangular jumper plug.

If the jumper is to be
turned off, connect it to just one of the two terminal pins
as shown in the figure below. By doing this, you can
avoid losing the unused jumper plug.

10

Jumper settings
The tables below give you information about the

interface conditions that can be selected using jumpers.
In all cases, ON denotes the connection of the jumper
(covering both terminals), while OFF denotes the
disconnection of the jumper.

11

If the host computer is not equipped with a power

1.
supply for the Current loop interface, these
jumpers must be connected to perform communica­tion via the Current loop interface

2

Either J8 or j9 jumper is connected at the factory,
and you should not change this setting

3.

Either JCX or JCF jumper must be connected.

4.

Either JCL or JRS jumper must be connected.

Jumper settings for RS-232C and current loop

Refer to the table below for information on the four

available handshaking protocol selections.
Table 7. Protocol selection in RS-232C mode

Table 8.

I

Protocol selection in Current Loop mode

JCL

OFF

12

1

serial data communications
The C82302*/C82304 interface allows you to select

either RS-232C or 20 mA Current Loop signal leve
data communication but never both at the same time

This interface board also provides for either DTR (Data
Terminal Ready) or X-on/X-off handshaking protocol.

About data entry
To accommodate data entry, the C82302*/C82304*

interface board is equipped with a buffer that temporar­ily stores data before transferring it to the printer When
this buffer becomes full, any additional transmitted data
cannot be accepted and is discarded. To prevent such
data loss, special handshaking protocols are provided

regulate the flow of data transmissioh llletwopmb-

a3l6wa5bletmthec823o2*-intataabotrd
areIYrRandxar/xoff.
Toenablethedablatbytothebuffer,DSRandDcD
mustkhcidatthcpositive~levcl(SPACDarDIP

switch2-Smustbeoff. WhenDIPswitch2-5isonand

.eitkDsRorDcDi66ettothenegativeEIAlcvd

fhiARTQ,allraxivingdatawiIlbeignoredbythe
c823o2~~iIl~boald.

13

Handshakingprotocol
x-on/x-off
X-on/X-off

Protocol

protocol is a system in which the printer

transmits a code to the computer to indicate that it
cannot accept more data, and a second code when it is
once again ready. This protocol can be performed under
either RS232C or 20 mA Current Loop signal levels.

The C82302*/C82304* interface board sends an X-on
<11>H

code

when it is ready to receive data, and an X-

off

<13>H

when

it is busy. The X-On/X-off

be transmitted from the TXD

ten&al

Signals

at

RM32C signaJ

may

kvels,orthroughthelTY-TXDWat28mA
currentLooplevels.

Note

X-on/X-off protocol cannot be performed when the
buffer

operation

is disabled. But the DTR flag protocol

is still possible.
After the X-on flag has been set, data can be accepted up

to the maximum capacity of the buffer.

l

Transmit timing of X-off signal

The X-off signal is transmitted when the vacant area
for bytes in the buffer drops to 512 or 16 bytes
(selectable with DIP switch 2-6).

l

Dati tn?nsjkapnx+igmll

Data can be sent to the printer even after the X-Off
signal is transmitted as long as sufficient room for
data remains in the buffer.

However,

if the transmit­ted data exceeds the vacant area in the buffer, it will
be discarded. X-off character will be transmitted
again when the remaining buffer capacity is actually

<08>H

0 bytes. At the same time, BS code

<2F>H

character

will be sent to the printer.

and “/”

14

l

Tmusnrit timing

ofXon

signal

neX4nt6lgnalis-tiwhe!nthepowerisfirst

tumedon,orwhenthevauntaminthebufferk

greater than the preset value of the buffer recovery

timing. Refer to Table 5. for buffer recovery timing
information

Figure 3. X-on/x-off timing

DTR protocol
This interface board also provides for DTR handshaking

protocol using either RS-232C or Current Loop signal

levels

Under this system, when the printer is turned on the
DTR enters the SPACE state, meaning that data entry is
enabled. When the rate of data reception is greater than
that of printing, the buffer gradually fills up. once the
vacant area for transmitted bytes drops to 512 or 1
bytes, the DTR sets the status flag to prohibit further.
data entry. This flag is output through the DTR (pin No.

20) under RS-232C signal levels, and through the TTY­TXD (pin No. 17) under Current Loop levels.

15

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’ tucontinuatopxinL

WhenthtMclntUeafor

ra&u~thepresetreaweryvaIue(seeTab~5Me

G

flagisresetanddataartybagainarrbled-

Note

~channtl(pinNo.11~andDTR~~No.zD~uc
intwLuyamneckdontheinterfaaboardandmwt

have

idmtid

When

buffer operation is disabled

UAdatttiswnditi~the5gisoutputfromtheDTR
(pinNo.u))intheQseofRs232GudfromLhc’I?y-

I7CD@inNo.l7EnthecaseofCumnt~.

DukngbufferdisabledoperatioAonlyasi@bytcof

dataanbehandledatatime

transfersabyteofdabtotheprhkr,thcstatus5gWill

be~Afterthfsdataisprillt6d,th65gwiIlrr#t,d

&laeAtlywilIbeenabledagah
PriAterrhtustrrm

lhe5gwilIbesetimmedlately~essdthc
rex&iIlgbufferupalityifthepriA~mchaa6trkd

error.
low.

signal

levds.

OMetheinm

lheerrorsignalQinNo.lof~winthcnk

16

nwseutatmodaankdtcredbyDIPswit&,2-7

d24. Toselectasdftestmukfhttumofftht

powatOthtphlbEfd~~changeDIPSWitch
settbg. wluAtkpowerLtumedba~ohthencw

settings

8&tES&tWIloffthcpowaudrl%!tth4?DIPswiteha.

Table 9.

automatiully
Self

modes

WmC intO tffuL

To

ait

i&n t&

17

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WhenthtMclntUeafor

SPECIFICATIONS

Synchronizing

Baud Rate:

Word length:

Start bit:
Data bit:
Parity bit:
Stop bit:

Input signal polarity:

1)

WithRS232Cz

MARK = logic “1”
SPACE = logic

2)

Cumnt

MA

SPACE

Method: Asynchronous

75,110,134.5,150,200,300,600,1200,
1800,2400,4800,9600,19200

(selectable)

1 bit
7 or 8 bits
Odd, even or none (selectable)
1 bit or more

loop:

RK = logic “1” (Current ON)

= logic

klectable)

f-3

to -27V

‘0” (+3

“0”

(Current

to

BPS

+m

OFF)

5. Handshaking

Tub& 10.

usingMRFrotoco1*

Handshaking

RW32C

whcntherigvl

conditionrtpinN0.11 bawccnpinNo.17

andpinNo.2Ois:
~~~t.Lnhyh

ccmtrol laop

w-hmtheimpedme

andpinNo.ML:
WWOVlARJQI)rtA

enhyidiubled.

mu

mmisbnsmittedby
tbedungeoftbe

impedAncebctwcen

pinNo.17andpin

No. 24.

xau

4btf

entry

xon <13>~

entry

mktr

is enabled.

mu

is disabled.

EsXaN/Xam

l

DTR signal can be fixed SPACE by jumper JRF.

Datl is-ttd

fmmpinNo.2

~4x4 CY I>K

entIyisenAbld.

xam CI~X~Z

entry h

disabled.

mm

TXDsignalcanbefixedh4ARKbyjumperJRX.

(No transmission of X-ON/X-OFF characters from

TXD.)

Note

&ration
k&p

is not

mode at

ratg

maranteed

when using the current

over 1200 BPS.

-

I/F board connector :EIA standard 25-pin Cannon

1.

type.

2

For signal description and pin assignment, refer to
the table below:

Table 11. Signal Description and Pin Assignment

IPin

No. 1

Simul Nmc 1Dirution’ 1

Protectiw

1

Gnlund

Truumitted

2

Data

CIXD)

-

out

-gmund

TrrMmitted 5eriAl

DcraiptiOll

data

I

I

4

6

20

Rquat to

Smd CRTS)

nmbtl cd

’
I-

Data TamlNl
hdy (DTR)

This

sigml

is

out

podtive ETA

bweitthepduityd-thb*gnal

Out bytheDlPrwit&l~.aranfii

thepomtliveEIAkwibythe
iumprP=

&qa

level.

at the

Note
1

The column heading “Direction” refers to the
direction of signal flow as viewed from the printer.

2

All signals except TTY-TXD and TTY-RXD comply
with EIA RS-232C standard.

21

RECOMMENDED CIRCUIT CONNECTIONS

Recommended line driver and line receiver for RS-232C

signal level settings., (As viewed from the host com­puter.)

Figure 4. RS-232C

MC

1499L

75199 or

!Sefial Inteffaa

0quivMnt

Boafd

Recommended line interface circuit for 20 mA Current
Loop signal level settings. (As viewed from the host

computer .)

Fipre

5.

Currmt Loop

I

I

Note
The value of “R” should be selected so that the loop
current is set between 10 and 20 mA. The u+V” should
be 3v to 24v.

22