TRIM phones were distributed from 1965 by the GPO (the equivalent of the PTT in the United Kingdom), as the first phones equipped with an electronic ringer. Previously, the phones were equipped with, as in France, a mechanical Bell.
Series of phones TRIM are identical replicas, except near the buttons, which have been revised to more modern models, and therefore more reliable. The TRIM phone can connect on a classical phone line, but also behind an ADSL Box. It has a function and a 3-position adjustable ringtone volume (high, low, off).Specifications