At 11:20 AM 01/23/10, "skipp025" <skipp...@yahoo.com> wrote: > > > "na4it" <na...@...> wrote: > > > It is connected to 2 Mitreks, with COS and PTT both positive > > voltage for action. > >There are a lot of different mods and connection points possible >in the Mitrek, so we'd have to know a bit more about how the >radios are connected. I've seen three or four different Mitrek >Conversions posted at various web sites and all are different >variations... > >Don't be scarred by active high or active low TX keying or COS. >It only takes a simple (properly connected) fet or transistor >circuit to invert the logic to the converse.
The positive voltage on the COS is easily changed with one transistor. The positive voltage on the PTT is an option in the original Mitrek design and if the radio is stock, is easily changed with one jumper in the control cable connector. For normal ground-for-PTT just apply +12vDC to pin 12, and then pin 13 is PTT (to ground). For +12-for-PTT, you would ground pin 13 and apply the +12 to pin 12. All of this is covered on the Mitrek page at repeater-builder. Go to www.repeater-builder.com, click on Motorola, then on Mitrek, then scroll down to the article titled "Interfacing the Mitrek mobile radio to your repeater controller", in the PTT section. Mike WA6ILQ
