Recently, I decided to finish up a project that’s been on the shelf for several months now. I was going to convert an analog MTR2000 into a P25 machine via an MMDVM.
I used the excellent STM32_DVM and associated cable from Repeater Builder. I have three of the STM32_DVM’s and they work great. Easy to tune, etc. Scott also has a native MTR2000 card now, too. However that was not available when I bought mine.
Anyway, I needed to reprogram the repeater to change the frequencies as my coordination differed from the test pair I was using. And that’s where the problem started.
Searching everywhere, I could not find my programming cable. So back to the bench to make one…. After researching the pinouts, it is very simple, I ran into having to translate from the examples online looking into the radio jack, to the other examples looking at the RJ45 connector, but from which side?
Much trial and error later and after reviewing my notes, I thought I’d share my revelation:
- Get a T568B ethernet cable, probably the most common out there, and cut off one end.
- Get a DB9 female connector, with clam shell, etc. if you want to make a keeper
- Soldier the white/blue wire to pin 5 of the DB9
- Soldier the green to pin 2 of the DB9
- Soldier the white/brown to pin 3 of the DB9
- Attach your clam shell and cable retention
- Program your repeater!
