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UHF Allstar node under construction. It will be set up on 446.150 (PL 100.0Hz) simplex node for now in East Asheville, NC. Hopefully this $3 china CM108 adapter will have a functioning GPIO like the internet said it would... RPi SD card is imaging as I type.

@n4vx
If your CM108 adapter does work, post specs?

@Sabex It seems to work great during local testing. The Maxtrac wants a LOT of Vpp input for proper TX deviation but otherwise it has been pretty much plug and play.

The CM108 came from eBay, link below:
ebay.com/itm/CM108-USB-Drive-F

The mod I performed was from :
garydion.com/projects/usb_fob/

@n4vx
That looks like a much more sensible mod. Why not just use the audio outs on the sound card though?

@Sabex @n4vx PTT most likely. Just a shot in the dark.

@Kalvo
O_o

Right who can tell me - COS: what does it stand for?
@n4vx

@Sabex The 3.5mm TRS jacks on those sound cards are extremely poor quality. I intend to place this in permanent service with the sound card in a project box when it is complete. I prefer to have all my connections soldered or connected with a locking type connector if possible. Its a lot of effort on the build but hopefully a lifetime of service with no flaky connections.

@n4vx I've been looking into your CM108 build.
The COS line is an input to the soundcard that notifies the repeater that the squelch is open, correct? Could it be driven from a handheld's signal receive LED?

@Sabex that should work but PL/DPL may cause some issues depending on the radio. If the LED turns on with any signal but the squelch stays closed due to lack of correct PL/DPL, you may get erratic results. If the LED only comes in after a correct PL/DPL decode then you should be good.

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