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APPENDIX
Appendix C: Serial interface

C-1. Connectors and Signal Names (Serial Interface)

Pin No. Signal name
Direction
Function
1 F-GND – Frame ground
2 TXD OUT Outgoing data
3 RXD IN Incoming data
4 RTS OUT Request To Send: The printer sets this signal
on “SPACE” when it is ready to send.
5 CTS IN The host sets this signal on “SPACE” when it
is ready to send. NOTE: The printer does not
monitor this signal.
6 N/C Not used
7 S-GND – Signal ground
8 ~ 10 N/C Not used
11 R CH OUT The printer sets this signal on “SPACE” when
it is ready to receive. This pin outputs the same
signal as pin 20, to which it is connected.
12 N/C Not used
13 S-GND – Signal ground.
14 FAULT OUT The printer sets this signal on “MARK” to
indicate an error condition (machine error, no
paper, etc.).
15 ~ 19 N/C Not used
20 D TR OUT Data Terminal Ready: The printer sets this
signal on “SPACE” when it is ready to receive.
(1) DTR/DSR mode
Space when receiveis enable.
(2) X-On/X-Off mode
Always space except during following
states
• Period between reset and communica-
tion enable
• During self printing
21 ~ 25 N/C Not used
13 1
14
25