RTS Request to Send
Clear to Send
Pin 8 Pin 1
Figure A.1: Serial Port Interface
Appendix A. Interface Description
A.1. Serial Port (RS232)
DCD and DTR hardware lines function as follows:
1. When connected:
a) If either port is set for Modem Mode, the DTR output at either port reflects the
DCD input at the other end.
b) If neither port is set for Modem Mode, DTR output is held high (active).
2. When not connected:
a) If the port is set for Modem Mode, upon disconnect DTR output is pulsed for
0.5 seconds and then held high.
b) If the port is not set for Modem Mode, DTR output is controlled by the DTR
Output option (Serial Port Parameters Menu, Option 23). Upon disconnect,
Option 23 allows DTR output to be held low, held high, or pulsed for 0.5
seconds and then held high.