Appendix A Cabling for RS-232 Port 81
25-pin NULL Modem Cable:
Remoet host
serial port
connector
Calling system
serial port
connector
Signal
2
3
Transmit Data
3
2
Receive Data
4
5
Request to Send
5
4
Clear to Send
6, 8
20
Data Set Ready
and Carrier Detec
7
7
Signal Ground
20
6, 8
Data Terminal
Ready
