Motorola’s Radius GP and GM series radios are now cancelled. But there were so many of these radios sold that there are still many around and still in use today! That’s why we’ve put together this guide to programming the Motorola Radius GP300 series two way radios.
NOTE: This guide does not tell you how to program the Radius GP300 and GM300 series radios. It outlines what you need to program them. If you would like to learn how to program these radios, we will link to a few guides at the bottom of this page. You might want to join this dedicated group on Facebook.
Portable radios covered by this guide:
Mobile (vehicle) radios covered by this guide:
It probably goes without saying that the portable radios and the mobile radios in the Radius GM/GP series have different programming cables. The portable radio is programmed via the back of the radio. Whereas the mobile (vehicle) are programmed using a cable that plugs into the front of the radio*.
* There is a method of programming the GM300 and GM350 radios from a connector on the back. We do not cover that method in this guide as there is not enough information about it.
Prerequisite: USB to Serial Cable
No matter what radio or cable you will need to use, if you do not have a COM port directly on your PC or laptop, you will need a USB to Serial cable. It is important that you buy an FTDI chipset USB to serial cable.
Buy from Radiotronics UK: http://www.radiotronics.co.uk/startech-icusb2321f
Portable Radio Programming Cable
Radios covered: GP300, P110, GP350, GP280 & GP88
The portable radios in this series are programmed using a cable that connects to the back of the radio. Because the programming kit replaces the battery, you will also need a 9v supply. Unfortunately, the original cable is long since discontinued by Motorola. But there are some aftermarket replacement cables.
Note: The GP300 and GP350 have a different battery profile and therefore require different cables.
You can buy these cables from our friends at RadioArena here:
- Radio Arena Programming Cable for Motorola GP300 & P110
- Radio Arena Programming Cable for Motorola GP350
Mobile (Vehicle) Programming Cable
Radios covered: GM300 & GM350
If you have either the GM300 or GM350, you will be able to find a cable at Radio Arena here.
You can download the Radius GP300 software from Radiotronics UK free of charge. However, it must be noted that we can’t give you any help programming.
The software only runs on MS DOS, not Windows.
Please do not contact Radiotronics UK about programming this radio. Instead, you can find help in the following places:
- Facebook Group: https://www.facebook.com/groups/565482877488862/
- Software Service Brief: http://www.radioarena.co.uk/pdf/rsshlp.pdf
- Understanding Model Numbers: http://www.batlabs.com/models.html
- Identifying Your Radio: http://www.batlabs.com/gallery.html
- Nokiaman’s Video: https://www.youtube.com/watch?v=ikPXfpiwFwI
- Cable Reference: http://www.repeater-builder.com/motorola/rss/pdfs/rss-table-2003-08.pdf