Set/reset the DTR pin state upon startup

[rianadamian]

Required to resolve an issue that causes dead radio air each time our radio station (CKUT 90.3 FM) experiences a power outage. Each time our computer running OBS reboots, the DTR pin state is such that the connected switch to which OBS sends alerts selects the audio channel for alert broadcasts, instead of the audio channel that plays our broadcast. Usually nothing plays on the emergency alert channel, so this means we broadcast dead air and someone needs to go in to the station to select the proper channel. There is no way to manipulate the DTR pin state remotely even though the software can manipulate the DTR pin state.

This is true for the Henry Engineering Stereoswitch (supports GPIO) that we use; I am unsure about other switches.

It would be efficient for our setup if there was an advanced option in the OBS settings to set/reset the DTR pin state upon startup. At the moment we have edited the source code to inject a dummy test alert upon startup - this always ends with the DTR pin state such that the correct channel is selected on the switch.