I spent yesterday afternoon working on building my interface for the Motorola Radius GM300 I bought. Between that and having to watch the granddaughter, I didn't get the opportunity to test last night.
First issue. The GM300 RadioDoctor software that I downloaded couldn't find a dll file it was looking for. Seems that the file in question isn't necessarily available on Windows 7 x64. So after scouring the net, I found the file and instructions on where to put it and registering it on my system. After that, the program started up.
Hooked up the TTL converter to the computer, and Windows dutifully downloaded the correct drivers to make it work. Connected the other end to the radio, connected power to the radio, turned the radio on, and started up the software. The software was unable to find the radio. I looked to see if there was some way to set up the software to specifiy the com port to use, since I was sure it was a "non-standard" port number. No such setup was found, nor was any mention made of it on the net. Went into device manager, and changed the port so that it was COM1. That made a difference. At least the led's on the ttl interface were flashing indicating that the software was trying to communicate. But it was still unable to find the radio.
I pulled the plug out of the radio to check the wiring there. Pin 7 was supposed to be the serial data, Pin 4 is ground. There seems to be conflicting information on the web as to what constitutes Pin 1 on an RJ-45 connector when it comes to Motorola radios. The correct answer is, with the cable end of the plug facing you and the pin end facing away from you with the retaining clip side pointed toward the floor, Pin 1 is on your right and Pin 8 is on your left. I had connected to the wrong pins the first time around. I had used a short piece of CAT-5 cable to make that part of the programmer, so it was a matter of identifying the correct color wires for those pin positions and then connecting those to the DB-9F I was using.
Connected everything back up, tried the software again, still no communication. I had noticed and commented that on the blog of the Fireman that his schematic diagram differed from the original one in that the diode was pointed the opposite direction. I had taken it upon myself to flip the diode when doing my assembly. So on the off chance I was wrong, I took things apart and rewired it with the diode facing the direction that was indicated by the original poster.
Reconnected everything and tried again. This time both the tranmit and receive led's flashed, but still no communication with the radio.
As a final step, I went back to the Fireman's blog and re-read everything. Besides the diagram, he had also posted a picture of his final assembly on the DB-9F. After spending some time comparing the photo with the diagram, I came to the conclusion that the two didn't match. So I disassembled everything again, and built it so that it matched his picture from an electrical standpoint. I mention this because I was using axial lead parts that I had in the junk box, and he used chip style parts.
Plugged everything together, started up the software, turned on the radio, told the software to read from the radio. Drum roll please ... It worked! Wow. So I programmed in the frequencies for the local repeater. I have not tested the radio yet, but I'm hopeful. First I have to put together some sort of microphone for it since it didn't come with one. Should be able to bang that out in fairly short order.
On to the next order of business.
73
Steve
KDØWSW
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