AON PR-250 - Interface; Serial Interface

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2.3 Interface
2.3.1 Serial Interface
The serial interface of PR-250 printer is compatible with RS-232C, supports
DTR/DSR and XON/XOFF handshaking protocols, uses DB25 socket (female).
The pin order of the serial port is as Fig.2-2 shows:
Fig.2-2 Pin Order of Serial Port
The pin assignment of serial interface is shown in Fig. 2-3:
Pin
No.
Signal
Name
Signal
Direction
Source
Description
1
FG
——
——
Cover ground
2
TXD
Output
Printer
Printer transmits control code
X-ON/X-OFF and data to
host
3
RXD
Input
Host
Printer receives data from
host
4
RTS
Output
Printer
The same with 20pins DTR
signal
6
DSR
Input
Host
Signal “MARK” means the
host is busy and can not
receive data. Signal
“SPACE” means the host is
ready to receive data.
7
GND
——
——
Signal Ground