While reading any number of GMRS Facebooks groups, there are a number of questions about building linking nodes.

First let me say, I am NOT the radio police,

There is one group that deletes  posts If the poster even mentions "radio-less" nodes,

while another guy sells them.
Let me "back up" a bit, Radio (repeater) linking has been going on for years, both in the commercial world and amateur radio.
And I don’t even pretend to be an expert on the subject, what I think I know, as far as amateur radio is concerned ;
The early attempts were IRLP ( Internet Radio Linking Project), EchoLink , and later All-Star.
These are ALL analog radio linking schemes ( Not digital radio, which is another mode, and will not be covered here.)
I am not going to get involved in the politics of this OR the GMRS linking politics, but will try to explain what I know about both.
When we talk about amateur radio linking, I will just jump straight to ALLSTAR , as the others have no place in this discussion.
When we talk about GMRS linking, I can only tell you what I think I know, because it seems to be a BIG secret.
When we talk about ALLSTAR there is even more politics . The way I understand the process, goes something like this:
Sometime in the early 2000’s there was a group of software developers working on a telephone PBX ( Private Branch Exchange)
Software, that is used by most telephone vendors today ( lets just pretend I know what I’m talking about here )
One of these early developers was also an amateur radio operator and saw the possibility of using it to link amateur repeaters.
Here is where the “politics “ start, Jim ( who is now “SK” ) helped write the original ALLSTAR software, and another group “HAMVOIP”,
Developed a fork off of the original. So now when I refer to ALLSTAR the two should be considered “interchangeable”.
Enter GMRS, I don’t know about all of the GMRS network operators, but one of them does not like to be referred to as
“ALLSTAR for GMRS “ but no matter how you cut it, it is.
This is just a little background of what I think I know.
I will be adding links to some articles I have found as well as some more of MY thoughts.

Don, K8ZGW

I have noticed that there are any number of people that are looking for information about
internet linking of radios ( ROIP )
There are a number of GMRS facebook groups, as well as amateur radio groups that sometime
ask about "all star " nodes.
There is one gmrs group that "removes" my posts, because the moderator has a small mind,
and thinks it is illegal to link on GMRS, while there are at least three networks that I know of
that are doing just that, it is not MY job to decide what is legal, YPYMATYC .. ;-}
While this site is "aimed" at the amateur radio community, GMRS is radio too.
and a "radio check " is just the gmrs equivenent of "CQ" ...
This part of the page will be made up mostly of <links> with attached comments.

I know of several Radioless nodes that have been built around the Masters Communications RA25

Pin 1 going to your audio amp.
microphone audio should go into the Disc input of the RA25.
the PTT switch from the microphone to the cos input.
You will need to adjust the mic audio level with the disc potentiometer.
you can also use the Tx PTT output of the RA25 to an led and 1K resistor to plus power supply,
thus giving a “Incoming Signal” indicator when the volume gets turned down and forgot about.

9 pin RA adaptor to radio

1 Audio out right
2 Audio out left
4 ctcss
6 Disc - mic audio hi
7 not used (special)
8 Gnd
9 not used

Since I have built the one I built, Kevin ( the owner of Masters Com ) has brought out another
radio adaptor, designed for a "radio-less" node, the MC-RL-20, that may be a better fit.

he RA-25 has a communications status monitor that, among other things, prevents a stuck PTT if the software crashes - the RL-20 doesn't have this.

The RL-20, when used as a radio adapter, the status of the COS can be shown with an onboard Yellow LED. This LED is driven from a CM119A GPIO when commanded to do so in software - the RA-25 doesn't have this.

The RL-20 is physically smaller in size.


Here are a few links to some interesting papers by verious authors on the subject

Allstar-Node Setup and Configuration-Guide

Allstar Newbie Guide

Allstar Radio Fara talk

Gmrs Notes


This is a link to the ALL-STAR beginners guide

Here is a link to the ALL-STAR web site

If you want register a node
You will need a valid amateur radio call sign.