Provides 20 dB of attentuation to condition line level audio to and from the (tr)uSDX to prevent overload and distortion of signal in digital mode operation.
Assemble the adapter, and plug into (tr)uSDX with resistors facing down. Note board labels for each plug. Insert a TRRS cable into the adapter. Connect audio cable to computer or phone TRRS combo jack, or to headphone and mic jack using a splitter. Set (tr)uSDX volume to 10. Set computer/phone audio volume level to 100%. To trigger PTT on transmit, either set up CAT control or use VOX mode.
Solder resistors in labeled positions on board and trim leads.
Solder TRRS 4 pin jack onto board.
Install TRS plugs into radio sockets with solder pins pointing up.
Place board onto TRS plug solder pins with resistors facing down. Solder into place.
2ea. TRS Pins Plugs: https://www.digikey.com/en/products/detail/tensility-international-corp/54-00036/5609421
2 ea. 10k ohm 1/8w resistors: https://www.digikey.com/en/products/detail/stackpole-electronics-inc/CF18JT10K0/1741566
2 ea. 1k ohm 1/8w resistors: https://www.digikey.com/en/products/detail/stackpole-electronics-inc/CF18JT1K00/1741612
(Or equivalent through hole resistors)
1 ea. 3.5mm 4 pin jack: https://amzn.to/3NtxQJv (Amazon affiliate link)
1 ea. TRRS cable: https://amzn.to/3NpYUt5 (Amazon affiliate link)
1 ea. TRRS to dual TRS splitter: https://amzn.to/3xZaCFw (Amazon affiliate link)