Ds1 Facilities - AT&T MERLIN LEGEND Release 2.0 Equipment And Operations Manual

Lines and Trunks

DS1 Facilities

A Digital Signal 1 (DSl) facility is a transmission system that transports digital
signals in the DS1 format. The interface that allows the connection of DS1
facilities to the system is the 1000 module. Through this module, voice and
data calls can be made or received using a DS1 facility.
Twenty-four digital signal 0 (DS0) channels, each operating at 64 kbps, plus
framing bits, are multiplexed, forming a DS1 signal of 1.544 Mbps. Each DS0
channel within the DS1 signal corresponds to a logical endpoint. Even though
there is only one physical jack, the 10013 module supports up to 24 logical
endpoints or ports (one for each channel).
In DS1 format, calls to other digital private branch exchanges (PBXs) or
telephone company CO remain digital, and signals do not need to be converted
to analog for acceptance by the connecting trunk. In addition, the 100D
module can be configured to work with T1 or Primary Rate Interface (PRI)
service.
To connect the 100D module to an outside DS1 facility, a CSU is used. The
CSU regulates the transmission into and out of the 100D module so that the
module matches the transmission of the outside facility.
Both ends of the DS1 facility must be able to communicate. To ensure this, the
following options are set during system programming to match the transmission
of the outside DS1 facility:
Type of service (T1 or PRI)
Framing format
Line code
Line compensation
Clock synchronization
Signaling mode (for T1 service only)
The appropriate setting for each option is determined by the transmission
facility to which the module is connected. Each option is discussed below.
Type of Service (T1 or PRI)
The system supports two types of service for DS1 facilities: T1 and PRI. The
100D module can be programmed to operate in either type of service. T1
service transmits and receives voice and analog data; PRI transmits and
receives voice, and analog and digital data.
Any combination of the following AT&T Services Network (ASN) Services can be
provided through a T1 or PRI line/trunk:
3-16 DS1 Facilities