AT&T 2500 series User Manual
9-2
DATA COMMUNICATIONS CONFIGURATIONS
_
___________________________________________________________________________________________________________________________
_
___________________________________________________________________________________________________________________________
_
___________________________________________________________________________________________________________________________
DSC AND PSC CONNECTIONS
The dedicated switched connection (DSC) is a feature that provides a dedicated path using circuit-switched
facilities on the System 85 (R2V4) and Generic 2 communications system; the permanent switched
connection (PSC) offers a similar capability on the System 75 and Generic 1.1 communications systems.
DSC and PSC are implemented through communications system administration. No extra hardware is
required.
facilities on the System 85 (R2V4) and Generic 2 communications system; the permanent switched
connection (PSC) offers a similar capability on the System 75 and Generic 1.1 communications systems.
DSC and PSC are implemented through communications system administration. No extra hardware is
required.
DSCs and PSCs provide a clear channel through the communication system to connect two ports when
dialed number signaling is not provided on the incoming port. The channel runs at rates up to 64 kbps. A
variety of ports types may be connected through the dedicated communications-system path. They include:
dialed number signaling is not provided on the incoming port. The channel runs at rates up to 64 kbps. A
variety of ports types may be connected through the dedicated communications-system path. They include:
•
Analog line and trunk ports
•
DCP ports (digital-line ports on the System 75 [R1V2 and later] and Generic 1 communications system
and GPP ports on the System 85 [R2V4] and Generic 2 communications system)
and GPP ports on the System 85 [R2V4] and Generic 2 communications system)
•
EIA ports
Note: For EIA connections on the System 85 (R2V4), the bearer capability must be set to 2 on the trunk
group used for the connection. Set the bearer capability through PROC 103, field 15.
group used for the connection. Set the bearer capability through PROC 103, field 15.
•
DS0 channels of DS1 ports
Figure 9-1 depicts some typical DSC and PSC configurations. Other configurations are possible.
Note that:
•
24th-channel signaling and B8ZS line coding are required for certain dedicated (PSC and DSC) data
connections through the communications system.
connections through the communications system.
•
When a dedicated connection must be implemented between a System 75 or Generic 1 endpoint, and a
System 85 or Generic 2 endpoint, the connection should be implemented as a PSC on the System 75 or
Generic 1 communications system. Because PSCs can be established across communications systems,
no DSC is necessary on the System 85 or Generic 2 communications system when the PSC is defined
on the System 75 or Generic 1.
System 85 or Generic 2 endpoint, the connection should be implemented as a PSC on the System 75 or
Generic 1 communications system. Because PSCs can be established across communications systems,
no DSC is necessary on the System 85 or Generic 2 communications system when the PSC is defined
on the System 75 or Generic 1.
•
On the System 75 and Generic 1 communications system, PSCs can be defined at either of two
administration screens: the Permanent Switched Connection screen or the Interface Link screen. PSCs
established through the Interface Link screen are more properly called software connections, rather than
PSCs.
administration screens: the Permanent Switched Connection screen or the Interface Link screen. PSCs
established through the Interface Link screen are more properly called software connections, rather than
PSCs.