Honeywell CM4 - Communication Port

3 Rev. 2.4 (3/05)
Honeywell Analytics CM4 Protocol Manual
Communication
Port
Access to the CM4 protocol is through the COM port. This port is a DB-9
female connector. This port is designed for bidirectional communications
between the CM4 instrument and your equipment. Signals present at the
port conform to RS-232, RS-422, or RS-485 specications. Again, this is
based on which interface option was installed in your CM4 instrument.
The pin-out specications for each option are as follows:
RS-232 (Part Number 874270)
Pin Number Signal
2 Transmit
3 Receive
5 Ground
RS-422 (Part Number 874326)
Pin Number Signal
2 Receive +
3 Receive -
4 Transmit -
5 Transmit +
RS-485 (Part Number 874556)
Pin Number Signal
2 B (Transmit/Receive +)
3 A (Transmit/Receive -)
7 Signal Ground