Loud Bell/Ringer for Mobile/Cell Phone

[johnc83]

Hi, we have a noisy factory area where we need to reach people by phone and we need a loud ringer so the people can hear it ringing.

I am aware of loud external ringers but they only seem available for fixed LandLine telephones. I need one for a mobile phone. If possible I'd like a simple loud bell rather than speakers. Could anyone advise if it is possible to get something like this?

 

[Tha fios agaibh]

There's one called ringmaster on the market.
Or, you could design and build your own.

 

[Bluejets]

Most mobiles have a buzzer/motor vibrator.
One on my Iphone is difficult to ignore.

 

[andrea chiu]

I think you try this Algo 8180 SIP Audio Alerters. It works great as an external ringer.

 

[FuZZ1L0G1C]

I don't know if the Ringmaster or Algo 8180 have this design, but my idea is to have a small mike mounted in a cellphone cradle, with input sensitivity control, to avoid ambient sounds triggering it.
The relatively loud mobile ring (rectified audio) would trigger an alarm circuit via thyristor gate.