Return channel for closed circuit TV - has switch at subscriber end of optical fibre for reception or transmission of signals

摘要

The optical fibre connections distribute t.v. programmes to subscribers. A passive branch unit is positioned at the distributor end of the optical fibre. A switch is provided at the subscriber end. In one switch position the subscriber can receive the transmitted signals, and in the other position subscriber signals can be fed into the optical fibre. The t.v. programme is coupled from the central (2) to the optical fibre (LWL) via the passive branch unit (PA). Simultaneously, the information, e.g. programme selection transmited over the return channel (Rk) is disconnected.