A.1.2 Functions of each connector pin

 

Signal

Signal

 

Pin no.

name

direction

Function

 

 

 

 

1

FG

-

Frame ground

 

 

 

 

2

TXD

Output

Transfer data

 

 

 

 

3

RXD

Input

Reception data

 

 

 

 

4

RTS

Output

Memory Switch Msw 1-6 OFF: Same as DTR signal (Pin 20)

 

 

 

Memory Switch Msw 1-6 ON: Logical product of DTR signals of DM-D and TM

 

 

 

(If both are SPACE, the printer can receive data

 

 

 

(SPACE).)

 

 

 

 

6

DSR

Input

This signal indicates whether the host computer can receive data.

 

 

 

SPACE indicates that the host computer can receive data, and MARK indicates

 

 

 

that the host computer cannot receive data.

 

 

 

When DTR/DSR control is selected, the printer transmits data after confirming this

 

 

 

signal.(Except as transmitted using some ESC/POS commands)

 

 

 

When XON/XOFF control is selected, the printer does not check this signal.

 

 

 

Changing the memory switch 1-7 setting enables this signal to be used as a reset

 

 

 

signal for the printer.

 

 

 

The printer is reset when the signal remains MARK for 1 ms or more.

 

 

 

 

7

SG

-

Signal ground

 

 

 

 

20

DTR

Output

1) When DTR/DSR control is selected, this signal indicates whether the printer is

 

 

 

busy. SPACE indicates that the printer is ready to receive data, and MARK

 

 

 

indicates that the printer is busy. The busy condition can be changed by using

 

 

 

memory switch 1-3. (Refer to “Busy state” on page 4-9)

 

 

 

2) When XON/XOFF control is selected:

 

 

 

The signal indicates whether the printer is correctly connected and is ready to

 

 

 

receive data. SPACE indicates that the printer is ready to receive data. The

 

 

 

signal is always SPACE except in the following cases:

 

 

 

•During the period from when the power is turned on to when the printer is

 

 

 

ready to receive data.

 

 

 

•During the self test

 

 

 

 

25

INIT

Input

Changing the memory switch 1-8 setting enables this signal to be used as a reset

 

 

 

signal for the printer.

 

 

 

The printer is reset when the signal remains SPACE for 1 ms or more.

 

 

 

 

A-2Interface And Connectors

Rev. B

Page 130
Image 130
Epson L90 manual Functions of each connector pin, Rts