Rs-232 Serial Interface Protocols; Rs-422 - IBM 6500 User Manual

Receive Data (RXD). Serial data stream to the printer.
Clear To Send (CTS). Status signal to the printer indicating the host is ready to
receive data/status signals from the printer.
Data Set Ready (DSR). Status signal to the printer indicating the host is in a ready
condition.
Data Carrier Detect (DCD). Status signal to the printer. The ON condition is
required for the printer to receive data.
Transmit Data (TXD). Serial data stream from the printer for transmitting status
and control information to the host. Subject to protocol selection.
Request To Send (RTS). Control signal from the printer. Subject to configuration.
Data Terminal Ready (DTR). Control signal from the printer. Subject to
configuration.

RS-422

6500-v Models
Note: The RS-422 is optional.
Table 5. RS-422 Serial Interface Connector Pin Assignments
Input Signals
Signal
− Receive Data
(−RXD)
+ Receive Data
(+RXD)
+RXD, −RXD. Serial data stream differentially received by printer.
+TXD, −TXD. Differentially driven serial data stream for transmitting status and
control information to the host. Subject to protocol selection.
Note: ±RXD and ±TXD form signal and return paths of a differential line signal.

RS-232 Serial Interface Protocols

DTR. (DTE Ready). The printer controls the data flow by asserting or de-asserting
this hardware signal to the host. If there is enough room in the printer buffer, the
printer will send a high signal; if the buffer is full the printer will send a low
signal. DTR tells the host if it is safe to send more data (If the host sends data
during an unsafe condition, data will be lost.)
Output Signals
Pin Signal
1 − Transmit Data
(−TXD)
6 + Transmit Data
(+TXD)
Miscellaneous
Pin Signal
3 Chassis/Signal
Ground
8
Chapter 5. Printer Interfaces
Pin
5
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