The ToneCaller from BT, with its loud sound makes it easier to know when
your phone is ringing.
It features an extra audible alert if you are having problems hearing your telephone ring. With choice of 4 different pitch settings and a volume control, plug this additional bell into a spare telephone socket or use a socket adaptor to plug it in beside your existing phone.
Telephone lines usually have a REN of 4 ~ they can operate up to four
telephone products (e.g., phones, fax, answering machine) each with a REN of
1. This product has a REN of 1. Please note we also have REN Boosters
available if your REN exceeds 4.