GM360 Public Address Interfacing

[dave lee]

I'm installing a new system in a refinery consisting of 11 GM360 units with GP380IS handsets, and i want to interface one of the GM360's with the PA system for making emergency announcements from any of the GP380IS over the PA speakers.

My plan is to have one dedicated channel for this purpose, which will ideally output a line level audio signal with a PTT when this channel is acccessed.

Is there an interface or other facilities available that can do this?

This is my first foray into two way radios, so please excuse any nievity, I normally do the PA stuff.

cheers

[bw18]

Yes it is possible... You will need to use the GP I/O lines.

Not something I have really dealt with before, looking at the CPS it is fairly simple.

You basically assign the output to the pins on the back of the radio. I'm not exactly sure how you would assign a channel to that system so you can make PA's via a radio. I have seen it done though so I know it's possible...

One for you George?

[emsgeorge]

Just put the gm onto the 'tannoy' channel, and put a dedicated channel into the hand helds.

Cant remember off the top of my head the i/o lines, but you will need one of the accessory port kits, and a bit of mic cable.

It will be a line level output, then into a DI box ( if you need to take it to mic level).

Ive got some made up acc connectors to xlr somewhere, will look and see what pin outs I used. the acc port has got flat audio out.

hold on for a few hours, I will dig out the serivce manual when I get back.

[dave lee]

Thanks guys, this looks really encouraging. Do I need to have one gm unit dedicated for this purpose if it needs to be on the 'tannoy' channel?

[bw18]

Yes. I'm not sure if there is a way to set it so you can use it as a conventional radio until the point at which it needs to be an output... You would need to be able to trigger the 'PA' feature remotely to route audio through the pin-outs rather than the speaker!

Having a quick look through the CPS I can’t seem to find a decoder option to do this, and I'm not even sure if you can! Basically if you could set a 5tone sequence to tell the radio to go into PA mode this would be perfect. This could then be used as a conventional radio, but when the 5tone is received it kicks into PA.

However... I've just looked again on the CPS and found a drop down on the GP I/O lines for 'Open RX Audio'... SO this might be the answer!

I'm sure George will be back soon with some more info 

BW

[emsgeorge]

dave,

Easiest way - dedicate a radio to the channel you make the 'tannoy' channel. If you use a gm series, then you will need:

■HLN9457 accessory connecting kit (pins and the housing)

Some thin mic cable

XLR or phono or jack, dependant on inputs

Passive DI box (if you are using the mic input, as the line out from the gm is a bit hot for mic inputs)

If you use a proper motorola power supply, you can stick a small gel lead acid battery on it, so it will fail over if you loose mains to the cabinet. Even better if the PA amps are fed by a ups, just make sure it goes off the same supply.

Pins you need are pin 1 and pin 16. This is a speaker level out, so leave the volume on the radio low.

If you want the install manual, give me a PM with your email address.

G

[dave lee]

WOW, you guys are the dogs nuts i won't actually be doing this for a few of months yet, but i know how and what kit i need to order, no doubt you will here from me again when it all gets a bit sticky. but many many thanks, donation on it's way!