[arm-allstar] How to generate PL

[Tom Hayward]

I would like to generate PL any time the audio path (receiver or link)
is active, but not during hang time, courtesy tone, or IDer. I am
using a Raspberry Pi 2 (I have a spare RPi 3 and various PCs if
needed), the transmitter and receiver are CDM750s, and the audio
interface is a RIM-Maxtrac-RM. This seems to be a frequently asked
question, but I'm still not sure what the best practice is. Here is
what I understand:

- simpleusb cannot generate PL
- usbradio can generate PL, but distorts the link audio
- I could generate PL with the transmitter, but this would add PL to
the hang time, courtesy tone, and IDer. Not what I want. (Are the any
programming tricks I can do in the CDM to toggle PL generation?)
- I could generate PL with an external encoder, but it's still not
clear to me how to give it an enable/disable signal when the audio
path is active.

What is the best practice here? What have others done?

Tom KD7LXL