IBM RT Series Hardware Reference Manual page 452

Pin Assignment for Serial Port
The following figure shows the pin assignments for the serial port
in a communications environment.
External
Device
-
-
- -
-
-
-
-
Carrier Detect
Receive Data
Transmit Data
Data Terminal Ready
Signal Ground
Data Set Ready
Request To Send
Clear To Send
Ring Indicator
18 Serial/Parallel Adapter
1
2_
--
3
4
5
6_
-
7
8_
-
9_ -
-
-
Serial
Parallel
Adapter
9