I have an extra Uno R3 and a relay laying around that I would like to be able to use to key up my ham radio for digital communications. Most of the software on the computer side allows the use of a com port RTS or DTR in order to cause the radio to transmit. There are devices out there for purchase that watch for RTS or DTR and in turn key the radio but since I have the extra Uno and relay I thought I would just build one. There is no data transmitted over the serial port, the relay just needs to be switched on or off based on the RTS or DTR being high or low.
When I plug the Uno R3 in via the USB cable it creates a serial port on the computer. If I set this as the com port for use in my radio digital software and tell it to either use RTS or DTR how would I watch for that on the Uno? I know how to flip the relay...I just don't know how to watch for RTS or DTR or if it is even possible.
I've found a number of postings that say since the Arduino only uses 2 pin TTL it doesn't work with RTS DTR etc., which makes sense from a hardware perspective and only the 2 pins available for RX/TX. Does the virtual serial port support this concept?
Thanks,
Josh