bilingual basic rate interface (ISDN)

The bilingual basic access (BIBA) existed when both D-channel protocols, the national 1TR6 protocol and the European DSS1 protocol, were used in ISDN.

The bilingual connection type was connected to a DSS1 switching unit in the respective exchange, which meant that it was treated like a normal DSS1 connection from the point of view of the network. By means of a network termination specially developed for the bilingual basic connection, incoming DSS1 messages were converted for 1TR6 terminal equipment.