Serial interface, Appendix d: interface, D-1. serial interface – Star Micronics SP298 Series User Manual
Page 134: Pins and signal names

131
APPENDIX
Appendix D: Interface
D-1. Serial Interface
Pins and Signal Names
Pin
No.
Signal
Name
Direction
Function
1
FG
—
Frame ground
2
TXD
OUT
Transmission data
3
RXD
IN
Receive data
4
RTS
OUT
STAR Mode
When Memory Switch 4-D = 0: Same as DTR signal
When Memory Switch 4-D = 1: Always SPACE
ESC/POS Mode
Same as DTR signal
5
N.C.
Not connected
6
DSR
IN
• DIP Switch 9 = OFF
STAR Mode
Status of this signal is not checked.
ESC/POS Mode
In DTR/DSR communication mode when Memory Switch4-5 = 0, indicates
whether data receive from host is enabled or disabled.
Space: Receive enabled
Mark: Receive disabled
This signal is not checked in the X-ON/X-OFF communication mode.
• DIP Switch 9 = ON
This signal used for external reset. Printer is reset whenever signal is in mark
state with pulse width of 1mS or more.
7
SG
Signal ground
8 -19
N.C.
Not connected
20
DTR
OUT
Indicates whether data receive from host is enabled or disabled.
DTR/DSR Communication Mode
Space when receive is enabled.
X-On/X-Off Communication Mode
Always space, except during following conditions:
• Period between reset and communication enabled
• During self-test printing and dot alignment adjustment
21 - 24 N.C.
Not connected