long island ny
Thanks to the original author of the schematic I found on the Internet.
I modified it to suit my needs which is:
Using a 5 Pin Motorola Maxtrac as a link radio for IRLP.
The 5 Pin Maxtracs are much cheaper to find on Internet for sale sites.
Spending a few minutes to do the COS mod can save some money $$$
I got this suggestion many years ago, and people have since documented it on sites
Hope this helps someone else out there.
Update, I added some info about hooking up to the Motorola
Motorola Maxtrac Mic Jack Pinout
5-MIC AUDIO IN
MY PiRLP TO MAXTRAC CABLE
Motorola CDM to DMK URI Interface
URI 20 - CDM 7 GROUND
URI 21 - CDM 11 RX AUDIO (de-emphasized)
URI 22 - CDM 2 External Microphone Audio Input
URI 1 - CDM 3 PTT (Pgm in CPS)
URI 8 - cdm 8 PL and CSQ Detect/Talkgroup Detect (Pgm in CPS)
I recently purchased some more 16 and 20 pin connectors and pins for the Maxtrac and CDM radios.
Here are the part numbers from my Digikey order.
In this example I have pins 7 & 9 jumpered together so the radio turns on when voltage is applied to the radio.
I could also be acomplished by connecting 12v to pin 10 Ignition Input.
I wanted to make sure the radio powers up when voltage is applied and not have to worry about
pushing the front button. There is an Ignition control paramater in the CPS.
16 Pin Housings Digikey
20 Pin Housings