Otherwise known as a loud bell or loud ringer, a Tone Ringer essentially amplifies the ring signalling from your phone calls
There are two basic forms of tone ringer, a compact form with integrated speaker and a small amplifier. these will ring moderately louder than a traditional house phone.
Then there are the amplified tone ringers, an amplifier with one or more line inputs and a more powerful amplifier than the first type. these units are capable of a much louder ring signal and in most cases never get pushed harder than 20-30% of their full volume.
The first type is usually used in open area's like a a warehouse where volume isn't a huge issue but distance can be.
The amplified tone ringer is suited to noisy workshops and acreage. These setups usually employ an external horn speaker giving them directional sound output allowing the installer to focus the sound to where it's needed
A directional speaker used to cover large area's, in general these can be seen at schools and sporting events. when paired with a tone ringer, they allow the ring signal to be aimed. in factory environments they are aimed at the ceiling which allows us to bounce the sound over most obstacles.
As a general rule if you can't see the centre cone you wont hear the speaker very well.
many tone ringers also support strobe lights, strobe lights can be used in addition to the audible signal to indicate an incoming call. the light will travel further and quietly making a strobe perfect for indicating calls in situations where unexpected noise is undesirable, or noise is so excessive that hearing protection makes even tone ringers ineffective