Selective Radio Inhibit - what older models support it?

kanabecsys · Post by **kanabecsys** » Fri Jan 06, 2006 6:31 pm

Hello all

I am working with an organization to deploy about 20 or 30 VHF portables on the cheap. They plan to use them to talk into an old Micor repeater which, when finished, will be controlled by Asterisk's app_rpt extension and associated hardware.

One feature that would be very useful in this situation would be some sort of over-the-air selective inhibit function. I know that newer radios support it, and that it can easily be done on a trunked system, but both of those options are out of the scope and budget of this project.

So... how far back has Moto been supporting selective inhibit-type features in their portables? And is there any sort of add-on or hack that could be used to permit 'stunning' a radio that did not support such from the factory (i.e., some sort of tone-controlled device that would cut off the PTT)?

What's my best method of operation - or isn't there one for this case?

Keith

Josh · Post by **Josh** » Fri Jan 06, 2006 11:14 pm

What I don't get is why people are so interested in inhibiting radios all of a sudden.

You can't do bum-diddly with any radio unless it is running a protocol, such as MDC1200 that actually allows it. And at that, only a true console can even encode that command. Even so, radios such as my HT1250 has an option check-box as to whether I want selective radio inhibit to work or not, of course, I should NEVER run into that problem.

I use MDC for call alert mostly, and sometimes sel-call and radio check. PTT-ID does nothing for me, and I find it quite annoying, but that's all beside the point.

At work, we use HT750s on a repeater- none have MDC even enabled, so should one happen to "walk away" or something, there's nothing at all that can be done to disable the radio in any way, shape or form.

-Josh

kanabecsys · Post by **kanabecsys** » Sat Jan 07, 2006 11:17 am

Josh wrote:What I don't get is why people are so interested in inhibiting radios all of a sudden.

I don't know what's with the other threads regarding it, but in this case it's due to the fact that volunteers will often be using (and possibly losing or abusing) them.

Josh wrote:You can't do bum-diddly with any radio unless it is running a protocol, such as MDC1200 that actually allows it. And at that, only a true console can even encode that command. Even so, radios such as my HT1250 has an option check-box as to whether I want selective radio inhibit to work or not, of course, I should NEVER run into that problem.

I'll try to find more info on MDC, since I've only played with it on a limited basis.

I guess I kinda expected to be needing a dispatch console. If I could find an older/used one around, it would probably be a done deal (especially since they could put one to use for their regular operations anyway).

Also, I need to talk to the guy who's building that Asterisk-based controller. It would be really cool if there was some sort of option in it to pass or reject incoming audio based on a list of, say, MDC PTT IDs or PL/DPL tones (but I doubt there is).