TMU/12 (Refurbished) System card/unit

TMU Device containing tone receivers for dial tones and DTMF signalling, tone senders, multi party and inputs for "Music on hold". The printed board assembly Tone and Multi-party Unit (TMU) is a support-board in the Line Interface Module (LIM) of ASB 501 designed to provide tone receiver, tone sender, Music On Hold-input (MOH) and conference functions. The TMU can be initiated to handle A-law or u-law Pulse Code Modulation (PCM). Refurbished.