Telephone Hybrids convert an incoming call into an Audio signal for the studio environment. The line echoes on analogue telephone interfaces which result from the 2-wire technology used are disturbing and must be eliminated by line echo cancellers.
To achieve the best results for the elimination of the echoes, digital procedures with signal processors are used in POTS Telephone Hybrids. However, in ISDN connections, no line echoes will occur due to the use of the 4-wire technology. If analogue telephone calls are received by ISDN Telephone Hybrids, echoes can also be detected due to the conversion from 2- wire to 4-wire technology in the analogue telephone unit. For clear communication digital line echo cancellers are also required.