Lucent Technologies Definity Enterprise Communication Server 8.2 User Manual

Issue 1

April 2000

Features and technical reference 

1396

ISDN service 

Refer to the DEFINTY services documentation for information about the 
following screens: ISDN TSC Gateway Channel Assignments, Network Facilities 
(supports usage allocation used in Call-by-Call Service Selection), and Signaling 
Group (used to define a group of B-channels for which a given D-channel or 
D-channel pair carries signaling information).

In ISDN-PRI, the transmission standard for layer 1 (the physical layer) is either 
DS1 T1 or E1. The DS1 T1 (used in North America and Japan) is a 
digital-transmission standard that carries traffic at the rate of 1.544 Mbps, and the 
E1 (used in Europe) carries traffic at a rate of 2.048 Mbps. The “D” (data) channel 
multiplexes signaling messages for the “B” (bearer) channels carrying voice or 
data. In a T1, when a D-channel is present, it occupies Channel 24. In an E1, when 
a D-channel is present, it occupies channel 16.

DEFINITY ECS offers several administrable protocols, each of which provides a 
different set of ISDN services. Refer to 

‘‘DS1 Trunk Service’’ on page 1317

 for 

more information. These protocols are discussed in detail later in this section. The 
following combination of services, including but not limited to Basic Call, Basic 
Supplementary Services, Supplementary Services with Rerouting, Display, and 
QSIG Networking are supported on the ISDN-PRI interface. Available services 
outside the United States vary from country to country.

With ISDN, DEFINITY ECS interfaces with a wide range of other products 
including switches, network switches, and host computers. These products include 
earlier DEFINITY communications systems, public network switches (for 
example, 4ESS, 5ESS, and Northern Telecom DMS250), and other products that 
adhere to the ISDN signaling protocol.