Lexmark 249X 用户手册
97
Section 6: Using the Printer Interface
Serial Cable Pin Assignments (RS-232C)
The following illustration shows the RS-232C serial cable:
RS-232C Serial Connector Pin Assignments
Pin
Signal
Description
2
TXD
(Transmit Data)
(Transmit Data)
This line transmits data from the printer to the host. The data
characteristics are specified by the function menu settings which are
read only during a Power On Reset (POR). The only data
transmitted are XON (x’11’) and XOFF (x’13’) signals. Transmission
occurs only when CTS is high.
characteristics are specified by the function menu settings which are
read only during a Power On Reset (POR). The only data
transmitted are XON (x’11’) and XOFF (x’13’) signals. Transmission
occurs only when CTS is high.
3
RXD
(Receive Data)
(Receive Data)
This line receives data from the host. The serial interface accepts
data only when DSR is On.
data only when DSR is On.
4
RTS
(Request to Send)
(Request to Send)
This line is set high and remains high even after the serial interface
finishes its POR.
finishes its POR.
5
CTS
(Clear to Send)
(Clear to Send)
This line is monitored only if the XON/XOFF protocol is selected
because transmission occurs only when CTS is high.
because transmission occurs only when CTS is high.
6
DSR
(Data Set Ready)
(Data Set Ready)
DSR is another method of providing data integrity. Data is accepted
only when DSR is high.
only when DSR is high.
20
DTR
(Data Terminal Ready)
(Data Terminal Ready)
This line is set high after the serial interface finishes its POR
sequence. However, if you select DTR pacing handshake protocol,
this line is used to indicate to the host whether or not the printer is
ready to receive any more data.
sequence. However, if you select DTR pacing handshake protocol,
this line is used to indicate to the host whether or not the printer is
ready to receive any more data.
25-Pin
Male
Male
25-Pin
D-shell
Female
D-shell
Female
13
25
1
14
25
13
14
1
Serial Adapter Side
Computer Side