Serial Port Connectors - HP Digital AlphaStation 255 Family User Information

Serial Port Connectors

The serial port connectors consist of two 9-pin D-subminiature connectors. Table B–7 lists
their pin assignments.
The baud rates supported by the system's serial ports are 50, 75, 110, 134.5, 150, 300, 600,
1200, 1800, 2400, 4800, 7200, 9600, 19200, 38400, 57600, and 115,200. The serial ports
have signals for full MODEM control. Refer to your operating system information to
confirm which of the baud rates from the preceding list your operating system supports.
Table B–7: 9-Pin Serial Port Pinouts
DB9 Pin Signal
1 DCD
2 RXD
3 TXD
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
Table B–8 shows the port mapping used by the OpenVMS operating system.
Table B–8: OpenVMS Port Mapping
Device
Graphics head monitor
COM1
COM2
Function
Data carrier detect
Receive data
Transmit data
Data terminal ready
Ground
Data set ready
Request to send
Clear to send
Ring indicator
Console Variable Value
Graphics Serial
OPA0 N/A
OPA1 OPA0
TTA0 TTA0
Technical Specifications
B–5