I scored a few older Motorola GM300 radios off of eBay and thought I
got a great deal. This soon changed when I realized the programming
options for this old radio were pretty limited. The first two things I
ran across was the “Radius GM300 Radio Doctor” over at http://www.g0hwc.com/motorola_gm300_gp300.html and the original Motorola Radio Service Software (RSS).
The GM300 Radio Doctor piece of software did a good job at being able to program this ancient radio with a “modern” OS like Windows XP. While it may be good at programming in frequencies and changing around the channel numbers, that is about all I was able to do with it. I really needed to be able to program the pins for the accessory port on the back of the unit, more specifically I need the COS pin to be enabled (see below).
GM300 Accessory Plug
Pin 8 is shown as “programmable” and unfortunately wasn’t enabled by default for me. So I opted to take some time to get the original Motorola RSS software running on my Windows XP laptop. To get started, you will need the following:
VA3WZW Andr.
The GM300 Radio Doctor piece of software did a good job at being able to program this ancient radio with a “modern” OS like Windows XP. While it may be good at programming in frequencies and changing around the channel numbers, that is about all I was able to do with it. I really needed to be able to program the pins for the accessory port on the back of the unit, more specifically I need the COS pin to be enabled (see below).
GM300 Accessory Plug
Pin 8 is shown as “programmable” and unfortunately wasn’t enabled by default for me. So I opted to take some time to get the original Motorola RSS software running on my Windows XP laptop. To get started, you will need the following:
- A machine running Windows XP (Haven’t tried this on Windows 7 yet)
- Motorola GM300 Radio
- Programming cable for the GM300. Mine is simply an RJ45 connector to
a DB9 (serial) connector. I picked mine up off of eBay for pretty
cheap. (~$8)
GM300 Programming cable - USB to Serial adapter. I use an old Keyspan USA-19HS that I’ve had
for many years. Looks like you can still pick these up for cheap on
eBay. I’m sure another adapter would work, but this is what I used.
Keyspan USA19HS - DOSBox software. This can be found here: http://www.dosbox.com/download.php?main=1. I used version 0.74 at the time of this article.
- Original Motorola GM300 RSS Software. This can be found here: - contact me for details.
Pease contact me here
instagram.com/va3wzw
good day how to adjust the frequency in low band in gp 88/gp 300 tnx 73
ReplyDeleteon line 10 above can you show exactly what to put if my port is COM6 Im not sure how to set this up I still get #7 – Invalid Opcode” and then “Radio Communications OK” I feel like this is the step hanging me up thank you!
ReplyDeleteYour steps above indicate
ReplyDelete"5. Now click on the Port Settings tab and set the baud rate to 2400, and make sure the other values match below:"
There are not any port setting listed.