ISDN point to multipoint connection

An ISDN multi-device connection is a passive bus connected to the network termination( NT). Several ISDN outlets(IAE) can be connected to the bus. The physical length of the bus depends on the configuration and ranges between 200 m and 1000 m.

Different ISDN terminal devices can be operated simultaneously on a multi-device connection. A maximum of 12 connection boxes can be connected in parallel to the multi-device connection with up to 8 ISDN terminal devices. The connecting cords to the terminal devices must not exceed a length of 10 m. In addition to single- service terminals such as telephones or PCs, multiple-service terminals can also be connected to a multi-device connection. With this type of connection, direct communication between the terminals is not possible. There are three different bus configurations for a multidevice connection: the short passive bus, the point-to-point connection and the remote passive bus.

The former configuration is a point-to- multipoint connection, the extent of which is limited by the signal propagation time and attenuation. This configuration allows a maximum extension of 200 m. The largest extension is offered by the point-to-point configuration, in which a terminal device can be set down up to 1,000 meters. The prerequisite is the use of a small PBX at the base station. The remote passive bus, to which four terminals can be connected, has a length of 500 meters.