ISDN stands for Integrated Services Digital Network. It uses a phone line to transmit data, but improves on speed compare to Dial Up. ISDN speeds range from 64 Kbps to 128 Kbps.
Consists of 2 types of channels:
- Bearer (B): Carry data and voice info at 64 Kbps
- Delta (D): Carry setup and configuration information and data at 16 Kbps
Common set up:
BRI setup, which consists of two B channels and 1 D channel. Only uses one physical line, but each B channel sends 64 Kbps doubling the throughput total to 128 Kbps. The D channel is 16 Kbps is managing the connection. The D channel set ups the connection and tears down the connection.
Primary rate interface (PRI) composed of twenty three 64-Kbps B channels and one 64-Kbps D channel, giving a total throughput of 1.5444 megabits per second (Mbps). Aka T1 lines. An E1 connection provides 30 B channels, 1 D channel, and an alarm channel. A PRI is commonly used as voice connectivity from the PSTN (Public Switched Telephone Network), which is your phone company, to a large (PBX) Private Branch Exchange local phone system inside of your company.
ISDN connects faster than modems, costs slightly more than regular phone line
Need to be within 18,000 feet of a central office to use ISDN
Use terminal adapters (TA)