Campbell COM200A, Instruction Manual, Page: 15 / 22

B-1
APPENDIX B. CS I/O CONNECTION
B.1 CS I/O 9 PIN CONNECTION
The pin out of the connector is shown in Figure B-1. The pins used by the modem are (unless specified
otherwise, all levels are 0 V for logic low, 5 V for logic high):
FIGURE B-1. CS I/O Pin Out
1. (input) +5 VDC supply
2. (input) Ground
3. (output) Ring - a logic high signifies a ring signal has been detected
4. (output) RX Data - serial data from COM200A
5. (input) Modem Enable - a logic high internally switches power to the modem. A logic low internally
shuts off power to the modem.
6. (input) Serial Device Enable - a logic high disables communication with the modem without
removing power or changing the modem's mode.
7. No Connection
8. (input) +12 VDC supply
9. (input) TX Data - serial data to COM200A