Lucent Technologies 2300EU System Administrator Manual page 80

Glossary
TEI – Terminal Endpoint Identifier
T
Up to eight devices can be connected to one ISDN BRI
line. The TEI defines which device is communicating with
the Central Office Switch.
TTI - Text Terminal Interface
The fax machine's telephone number and user name.
72 ISDN DEFINITY® Extender 2300EU/2100EU