Campbell Scientific MCR1 Memory Card Reader - Manual (Page 7)

A-1
APPENDIX A. RS232 D-CONNECTOR PIN FUNCTIONS
Pin Number Function
1 Protective ground, internally connected to pin 7
2 Tx receive data line, from DTE
3 Rx transmit data line, to DTE
4 RTS request to send, input from DTE
5 CTS clear to send, to DTE, normally held high by the MCR1
6* DSR data set ready, to DTE, held high at +5 V
7 Signal ground
8* DCD data carrier detect, to DTE, held high at +5 V
* directly connected to the internal 5V supply, do not short to ground.
1. Unlike the CSM1/ SC532, only RTS is required for telecommunications mode; the DTR line is
not used.
2. Only pins 2, 3, 4 and 7 need to be connected for use with the CSMCOM program. For
connection to a PC these pins should be connected to the equivalent function pins on the PC's
DTE interface.