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.