ISDN glossary
Service indicator A feature of ISDN. The service indicator, which is sent with every ISDN connection, indicates the type of connection required. If the service in- dicator of the calling terminal does not correspond to that of the called terminal, the connection is not established.
Standard rate access Service package for ISDN features.
System connection A particular type of ISDN connection. In the Euro ISDN, either the basic rate acces or the primary rate access can be used for a system connec- tion. The system connection is a
Toggle A special type of consultation whereby the two parties can be spoken
to alternately without interrupting the telephone connection.
TSI Abbreviation for ”Terminal Selection Identifier“.Used for the old German ISDN protocol 1TR6 (no longer widely used) to address a number to ter- minals connected to the same basic rate access. Nowadays, MSNs are used for this function.
Western plug General term for connectors with 4 or 6 contacts with analog terminals and 8 contacts with ISDN terminals.
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