Federal Signal's Model TELC Extension Ringer Device is a horn and strobe combination signal which is activated by the ringing signal of a telephone system. The TELC 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 TELC has a three–conductor, six–foot, 120VAC power cord extending from the unit. Connecting the TelCom device to the telephone network is accomplished by running a modular telephone line cord (RJ11) to an existing jack or a duplex jack (customer supplied) into an existing modular jack. The TELC is designed with a durable zinc die–cast housing painted with gray powder coat enamel, and feature an internal solid–state relay.

This combination audible/visual signal features the Vibratone horn and a three–dimensional strobe to notify when the telephone rings.

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.