Radio Tones

[waterfordfire]

Ok here goes,

I work for a rural fire department that has 2 base radios, motorola cdm750 and cdm1250 and is connected to an amp and speakers in the station.
I want to try and do 2 things
1. Set up the system so that the station speakers are only active from 6am to 7pm - hear all radio traffic
2. During the hours of 7pm to 6am the speakers only activate when the dispatch tones go off and do not activate when regular radio chatter occurs.

I am quite computer savvy but dont know a lot about radio systems. Any help would be appreciated

Kevin

[Al]

One solution would be to use the contacts on a plugin 120VAC timer readily available at any hardware store. You could program two separate personalities in the same channel bank(on the CDM1250 only), one for 7PM to 6 AM using quick call alerting with voice, and the other for just normal monitoring. The timer contacts would select one personality or the other using a channel steering pin on the accessory connector depending on the time of day. Contacts closed could mean a time between 7AM and 6PM, and open could signal that the present time of day is between 6PM and 7AM.
**caution** The cheap timers are designed to apply 120VAC to the outlet mounted on them. You need to open the timer up and modify for just a contact closure output. Otherwise, you will apply 120VAC to the accessory pins on your radios and release the magic smoke.

[RFguy]

or plug a 12-volt wall wart into the timer and have the wall wart energize a relay. Use the relay contacts to switch the adio to the hall PA.

As for only hearing the hall pages, have the radio's horn contacts trip a relay to activate hall PA audio for the duration of the horn activation (can you program it for 20 to 30 seconds, long enough for the dispatch audio?). Alternativly a timer relay activated by the horn contact to steer hall audio for a minute or 2.