AT&T 7500 series, 7100 series, 2500 series, 7200 series, 7400 series manual DSC and PSC Connections

9-2DATA 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.

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:

∙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)

∙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.

∙DS0 channels of DS1 ports

Figure 9-1depicts 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.

∙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.

∙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.