DP550 User's Manual
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Pin Description
RS-232 serial pin description is shown as table B-5:
Table B-5 RS-232 serial pin description
Pin
Signal Name
Direction
1
FG Frame Ground
2 TXD
Transmit
Data
OUT
3
RXD Receive Data
IN
4
RTS Request to Send
OUT
5
CTS Clear to send
IN
6
DSR Data set ready
IN
7 GND
Ground
8
DCD Data carrier Detect
IN
……
20
DTR Data terminal ready
OUT
……
Data bit format:
Data bit is fixed 8 bits, Stop bit is fixed 1 bit.
Baud Rate:
Serial communication baud rate can be set through menu setting:
1200 bps, 2400 bps, 4800bps, 9600bps, 19200 bps
Interface Protocol
The DTR from printer controls the data stream between printer and HOST. When DTR is high level,
it means the printer is READY, it can receive the data from HOST. DTR is high level in the following
conditions:
z
The printer is online
z
The data buffer area of the printer is larger than limited value.
z
The printer has no error
When the DTR is low level, it means the printer is BUSY, it can not receive the data from HOST.
DTR is low level in the following conditions:
z
The printer is offline
z
The data buffer area of the printer is smaller than limited value
z
The printer has error
X-ON/X-OFF Protocol
Send the X-ON (11H) code to the HOST from the printer through TXD, which indicates the printer is
FREE and can receive data from HOST. In the situation of the printer buffer area is larger than
limited value, the below two conditions can make the printer send X-ON code.
z
The printer becomes FREE from BUSY
z
The printer becomes ONLINE from OFFLINE
Send the X-OFF (13H) code to the HOST from the printer through TXD, which indicates the printer
is BUSY and can not receive data from HOST. In the following five conditions, printer sends X-OFF
code to printer:
z
The printer becomes BUSY from FREE
z
The printer becomes OFFLINE from ONLINE
z
The printer buffer area is smaller than limited value
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