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Interface timing, Serial interface, Transmission procedures – Epson EPL-6000 User Manual

Page 3: Serial interface pin assignments, Epl-6000 laser printer interface timing

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EPL-6000 LASER PRINTER

Interface timing

The figure below shows the timing for the parallel interface.

SELECT

DATA STROBE

BUSY

ACK

A: 1

(min.) 8: 1

(min.) C: 1

(min.) D: approx. 6

Signal levels

Output signals:

Input signals:

= 2.4 to 5.0 V

=0 to 0.8 V

= 2.0 to 5.0 V

Serial interface

The laser printers built-in serial interface can be set for either
RS-232C or RS-422A operation. These interfaces have the following
characteristics.

Data format

Word length: 7 or 8 bits

Parity: 0 or 1 bit (None, Odd, Even, Ignore)

Start bits: 1 bit

Stop bits: 1 or 2 bits

The data format can be set using functions and menu items in
SelecType.

Baud rate

300, 600, 1200, 2400, 4800, 9600, 19200 bits per second.

Signal level

RS-232C:

RS-422A:

= 2.2 to 12 V

to -12V

= 2.5 to 5V

= 0 to 0.5 V

Transmission procedures

Ready/ Busy:

l

The DTR signal level changes to HIGH when the printer is ready
to receive data (or to LOW if set for inverted operation by
SelecType).

l

The DTR signal level changes to LOW when the printer is not
ready to receive data (or to HIGH if set for inverted operation by
SelecType).

XON/XOFF:

l

When the printer is ready to receive data, it sends an XON
(11 hex) to the host computer through the TD line for the
RS-232C interface or SD+ and SD- lines for the RS-422A
interface. When ROBUST-XON is set to ON (by SelecType). and
data is not received within one second of the XON signal being
sent, the printer sends an XON signal every second. If ROBUST-
XON is set to OFF, the printer sends only one XON signal.

l

When the printer is not ready to receive data, it sends an XOFF
(13 hex) to the host computer through the TD line for the
RS232C interface or SD+ and SD- lines for the RS-422A
interface.

l

The printer is ready to receive data when it is on line, no error
conditions exist, and the buffer is not tilled above the overload
value set with SelecType.

l

The printer is not ready to receive data when it is off line or
when it is on line but the remaining capacity of the data buffer is
less than the overload buffer value.

Serial interface pin assignments

The serial interface connector pm assignments and a description of
the interface signals are shown in the table below. The direction of
signals is given relative to the printer.

Description

Frame ground. Safety

I

ground Iine.

Transmit data
This pin transmits serial

data from the printer to

the computer.

Receive data.
This pin transmits serial
data from me computer to

Request to send. This pin
is HIGH when power is on

Clear to send. This pin

indicates

that

the computer

is

ready

to receive data

from the printer.

Data set ready. This pin
indicates mat the

computer

is ready to communicate

Signal ground. This pin
provides a ground for all the
signal lines.

Send data. This
pin sends serial data from

the printer to the computer.

Signal level is RS-422A

Send data. This
pin sends serial
data from me

printer

to

the computer. Signal level
is RS-422A

Same as DTR. I
Receive data. This

pin

transmits serial data from
the

computer to the printer

Signal Ievel is RS-422A.

Data terminal ready. This

pin indicates

whether

or not i

the printer is

ready to

receive data. If the printer
ready protocol is not
selected, this pin is always

HIGH

(i.e. the printer

is

ready to receive data). If
printer ready

protocol

is

selected, the printer can
accept data when the pin
level is HIGH. and cannot
accept data when the pin
level is LOW. When busy i

Not a signal, but a +5V
power

supply

output.

Maximum of 300mA

Laser Printers 7/18/89

EPL-3