igiti- zation itself. A TE2 (terminal equipment, type 2) is a non-ISDN-capable device, such as a POTS telephone. In the event that a TE2 is used, a TA must be inserted between the TE2 and the NT1 to perform analog-to-dig- ital conversion and rate adaptation. The reference points mentioned earlier identify circuit components between the functional devices just described. The U reference point is the local loop; the S/T reference point sits between the NT1 and the TEs; the R reference point is found between the TA and the TE2. BRI Applications While BRI does not offer the stunning bandwidth that other more recent technologies (such as DSL) do, its bondable 64 Kbps channels provide reasonable capacity for many applications. The two most common today are remote LAN and Internet access. For the typical remote worker the bandwidth available through BRI is more than adequate, and new video compression technology even puts reasonable quality videocon- Figure 6-1 Channel 1 The ISDN Basic Rate Interface Signaling Channel (BRI) Channel 2 Switch Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Access Technologies Access Technologies ferencing within the grasp of the end user at an affordable price. Sixty- four Kbps makes short shrift of LAN-based text file downloads and reduces the time required for graphics-intensive Web page downloads to reasonable levels. The Primary Rate Interface (PRI) The other major implementation of ISDN is called the Primary Rate Interface, or PRI. The PRI is really nothing more than a T-Carrier in that it is a four-wire local loop, uses AMI and B8ZS for ones-density control and signaling, and provides twenty-four 64 Kbps channels that can be distributed among a collection of users as the customer sees fit (see Fig- ure 6-2). In PRI, the signaling channel operates at 64 Kbps (unlike the 16 Kbps D-Channel in the BRI) and is not a