Minilink Development Version 3
Early in the development, we found it necessary to provide compensating emphasis to the audio on receive. There appeared to be no degradation in the TX audio without emphasis compensation. Nevertheless, it may be that some situations might benefit from compensation on the TX audio, so de-emphasis was added to the options. Also, a connector ( 3.5mm TRRS type ) for the radio cable is added to the top PCB.
At about this time, we had concern about the continuity of supply of the chosen extruded alloy housing. We could change to a similar housing just 5mm wider at 40mm. We chose to go a little wider to 50mm and change the layout back to a single PCB. So the housing is wider, but a little lower at 20mm compared to the origional 26mm. So we need to find a larger box of matches and we contemplate version 4.