Specifications

2-6
Reference Guide
Model No.
Running Head
Voice Modules and Applications Applications
2.3.5 TR008 Application
BellCore’s TR008 standard describes the requirements necessary for a Local Digital Switch
(LDS) to connect to a remote terminal (RT) across a T1 (1.544Mbps) digital interface. The
standard allows supporting from one to four T1s per RT without facility Automatic Protection
Switching (APS), and three to five T1s with facility APS.
The LDS can interface the RT in Mode I (no concentration), Mode II (2:1 concentration), and
Mode III (24 special-service circuits on 24 DS1 time-slots). TR008 supports traditional POTS,
CLASS, and Coin services but does not support ISDN BRI.
If the service provider deploys a channel bank at the customer premise that does not provide
TR008 capability then it needs a 1/0 DCS with TR008 capability at the central office to
integrate with the LDS.
In addition to the many integrated access system functionality’s, the system also supports
TR008 switch integration. The integrated access system with TR008 operation can connect
directly to the LDS, eliminating the need for the 1/0 DCS as shown in Figure 2-2.
Figure 2-2. IAD using TR008
The TR008 feature can support 48 lines on 2 T1 links. This is an ideal vehicle to provide
integrated POTS services for line sizes of 48 and under. This system supports Mode I, Shelf
A&B of TR008 specification. The system supports extensive testing and diagnostics
capabilities which minimizes troubleshooting and allow high service levels.
POTS/
CLASS
D
S
X
P
A
N
E
L
Local Digital Switch
Customer Premise
Central Office
2 x T1/E1
IAD
• 48 TR008 Lines
• MODE 1 (Shelves A&B)