ISDN based Circuit Switched Services
Combines voice, video, and data over the same digital circuit
Sometimes called narrowband ISDN
Provides digital dial-up lines (each requires):
- An “ISDN modem” which sends digital transmissions is used
- Also called: Terminal Adapter (TA)
- An ISDN Network Terminator (NT-1 or NT-2)
- Each NT needs a unique Service Profile Identifier (SPID)
Acceptance has been slow
- Lack of standardization, different interpretations. and relatively high cost