Federal Signal's TELB TelCom Extension Ringer Device is a vibrating bell which is activated by the ringing signal of a telephone system. The TELB is specifically designed for use with an analog telephone. The ringing signal of 40–150VAC, 16–60Hz and local 120VAC power is all that is required to activate a TelCom signal.

This TelCom device is intended to be mounted on a vertical surface such as a rigid wall or post. The TELB has a three–conductor six–foot, 120VAC power cord extending from the unit. Connecting the TelCom device to the telephone network is done by running a modular telephone line cord (RJ11) to an existing jack or a duplex jack (customer supplied) into an existing modular jack. The TELB is designed with a durable zinc die–cast housing painted with gray powder coat enamel, and features an internal solid–state relay.

Telcom devices are designed for high ambient noise areas such as manufacturing facilities, machine and sheet metal shops. They are also useful in large open areas such as a warehouse, loading dock, or a large office.

This four–inch bell produces a 98dB signal @ 10' (108dB @ 1m).