There are two types of ISDN:

• Basic Rate Interface (BRI) -- consists of two 64-Kbps B-channels and one D-channel for transmitting control information.
• Primary Rate Interface (PRI) -- consists of 23 B-channels and one D-channel (U.S.) or 30 B-channels and one D-channel (Europe).

The original version of ISDN employs baseband transmission. Another version, called B-ISDN, uses broadband transmission and is able to support transmission rates of 1.5 Mbps. B-ISDN requires fiber optic cables and is not widely available.

Byte article on how the Internet will replace broadcasting 
A February 1996 article that discusses ISDN and MPEG mechanics as handled via Internet Web servers.

Dan Kegel's ISDN page 
This user page provides numerous links to many aspects of ISDN. Sample categories include: informational (what is ISDN?) , latest news, product development, company information, software and hardware, ISDN service providers, and links to additional Web resources.

Installing ISDN
Explains how to upgrade to ISDN.

ISDN Tutorial and Resources
Covers the basics of ISDN along with sections on history, advantages, interfaces, and links to Web references and sources.

PC communications over modems and ISDN
This article, from August 1996, describes serial ports, introduces the most general and least expensive ISDN equipment, and provides an outline of the steps to exploit this new service.

Yahoo!'s ISDN Page
Yahoo!'s directory of ISDN links.

Yahoo!'s ISDN user group page
Yahoo!'s directory of ISDN user groups.