Alerting System...can anyone help?

[Tabull]

Howdy All!
I have an situation where I need to alert our staff of an incoming call. The radio (spectra) is located in our Emergency Dept. and receives calls from incoming ambulances. We are on an 800MHz Type II trunked system of which we have little to no control over. The radio is located in an area that makes it difficult to hear if the volume is not turned up high. I would like to implement some type of Audio/Visual alert, probably a small ceiling mounted strobe and piezo buzzer arrangement. My problem is how to trigger it. I know the spectra offers a number of alert options, but which can I use without having to modify the radio in any way??? I can not have tones sent or anything like that so the best solutions seem unavailable. I would appreciate any help you can offer. Thanks! Tim

[RKG]

Provide the model # of the Spectra you are using. Most have a "horn/lights" function that enables you to wire the coil side of a small relay to pins on the accessory connector, which you could use as a trigger for your strobe or buzzer.

[Tabull]

I will have to get the model number, I am not in that immediate area...but I thought Horn/Lights required a "trigger", IE: MDC1200, tones, etc. Am I incorrect?

[wavetar]

Yeah, I thought it required a trigger as well, but haven't played with the feature in a Spectra.

I've done something similar for a customer. I used the DC biasing voltage which exists on either speaker lead when the radio is receiving. I ran that into a simple transistor switching circuit to activate a set of lights to indicate an incoming transmission. I also could have used it to drive a relay to run something bigger, such as a siren or similar.

Todd

[jmalia]

an easy way to d it is with a federal signal informer. not too expensive and they have relay outputs on them, you can cannect them to more relays to trigger strobes and lights. also get a PA controller to control volume, connect the speaker out from you spectra to the pa and connect the informer speaker out too, you will hear everything

[N4DES]

I know that you are looking for an external signaling device, but we have had great success with just using Call Alert from the field units to
the hospitals.

Basically if the hospital doesn't answer on its designated talk-group, the unit in the field has the capability to call alert any the hospital's 800 radios (16 separate hospitals to be exact). It was a win-win for everyone as EMS dispatch barely ever has to pick up the phone to call the ER and the field unit feels that they have a more direct feature without going through dispatch by scrolling through the list of hospital's and pushing the PTT.

Of course these capabilities will have to be programmed in but in the long run it would be well worth it if you could coordinate it.

[Will]

I've done something similar for a customer. I used the DC biasing voltage which exists on either speaker lead when the radio is receiving. I ran that into a simple transistor switching circuit to activate a set of lights to indicate an incoming transmission

Todd

Todd is on the right track. This does NOT require signaling to be programmed into the radios, ect;.

I would also add a small delay to trigering on the received voice to rule out occasional key-up drop-outs.

So, receiver has to un mute AND the voice gets detected, and that kicks in a relay to drive the strobe light.

This can all be done external to the radio without any changes to the radio.

[spareparts]

I did the same thing with an ST-ACR1M Audio Controlled Relay module from Radio Labs:
http://www.rdlnet.com/product.php?page=146