phone call triggers lights and bell

[OSHJunkies]

I was planning a simple project that turns on these vintage lights and rings a bell when you press a button - the lights and bells have sentimental value to many folks in my company - it was just going to be a stand alone little deal.  Then someone suggested I make the lights and bell go off when some one calls the office phone.  I think this is a great idea...but, I am not sure how to implement it - if fact I have no idea where to start.  The phones we have are VOIP, connected via CAT5 cables... I would prefer not to have to hack the phone - as they are CISCO and I may or may not reap the consequences for breaking one if I don't get it right the first time...but I would still consider this option.  Any thought on how I might pull this off?

[SeanB]

The ringer is probably a speaker on the bottom of the unit. Place a few dozen turns of wire as a coil around it and you probably will get a usable signal ( will need to be amplified around 200x and then rectified) that you can use to operate a relay. No contact, just the coupled magnetic field from the ringer speaker.

[sonicj]

Looks like you can pick up a used cisco voip tele for around $15 shipped on eBay. Might be best to experiment on one of those rather than explain to the boss why your phone is in parts spread across your desk and why you haven't answered any calls today.
-sj

[amyk]

The ringer is probably a speaker on the bottom of the unit. Place a few dozen turns of wire as a coil around it and you probably will get a usable signal ( will need to be amplified around 200x and then rectified) that you can use to operate a relay. No contact, just the coupled magnetic field from the ringer speaker.

A lot of VoIP phones use that speaker for the speakerphone function too. The ringing signal might need to be filtered out from that.

[yanir]

You might be able to hack into that used phone to directly control the lights via the LED ringer indicator, which most office phones have. Then put the used phone into a parallel group with the main phone. Both will ring and your lights will turn on.

[T4P]

You might be able to hack into that used phone to directly control the lights via the LED ringer indicator, which most office phones have. Then put the used phone into a parallel group with the main phone. Both will ring and your lights will turn on.

now that's voip he mentioned