Will the Tone Ringer work on my system?

The Tone Ringer (as is any other alarm or loud bell) relies on an analogue ring signal of around 40-70V at a "normal" frequency and periodicity. They will therefore not work on extensions connected to many key-systems (or a digital extension) because the ring-signal they receive is not a "standard" ring-signal.

If you can get a T200 or a buttinski to ring on the circuit you want to connect the alarm to, the Tone Ringer will work OK. If the test telephone/buttinski won't ring, neither will the Tone Ringer.