9
RXD
3
3
PCB board
Printer
receive
data
from
computer
TXD
2
2
printer
Printer
send
data
to
computer,when use X-ON/X-OFF
handshaking protocol agreement,
the printer will send control code
X-ON/X-OFF to computer
CTS
8
4
printer
When the signal show “MARK”, it
means the printer is busy and can
not receive data, when the signal
show “ SPACE”, it
means the
printer get ready to receive data.
DSR
6
1
Printer
when the signal show “ SPACE” it
means the printer is online
GND
5
5
－
Signal ground
DCD
1
Printer
Same as CTS
3-1 Serial interface pin number definition
Mark:
①
”Source” mean the source for the signal
②
The signal logic can be EIA or TTL level due to different insert sockets; Under
the serial interface connection, baud rate and data structure can be set by button or
software. Before out of factory, the product has been set with 9600bps, 8 data bits, no
calibration and a stop bit. Two types of handshaking protocol agreements can be chosen.
One is mark control way, the other is X-ON/X-OFF handshaking protocol agreement. Two
kinds of handshaking protocol’s instructions shown as figure 3--2:
Type of
Handshaking
Data direction
RS-232C interface signal
mark control
Data allowable
Signal line 1 and 8 are show Space
Data disallowed
Signal line 1 and 8 are show Mark
