AT&T 7300 series, 7500 series, 7100 series, 2500 series manual Distributed Communications System DCS

6. DISTRIBUTED COMMUNICATIONS SYSTEM (DCS)

_______________________________________________________________________________________

_

The distributed communications system (DCS) is a information system that provides a messaging overlay for main-satellite/tributary (MS/T) networks, electronic tandem networks (ETNs), or ETN-MS/T complexes that are designed for DCS implementations. This overlay provides communication among the network nodes so that the operation of a limited number of features is transparent across the network. That is, the operation of certain features is the same (or nearly the same) on each network node. In addition, DCS users can initiate calls to or receive calls from users on other DCS switches and enjoy the same feature capabilities as those that would be associated with the call were both users on the same switch.

This feature transparency is achieved by interconnecting all the network nodes with a signaling link that carries the information associated with a call. On the System 75 and Generic 1 communications systems, this signaling link is called the processor interface (PI) (formerly called the switch communications interface [SCI]) links. On the DIMENSION, System 85, and Generic 2 communications systems, the link is known as the data communications interface unit (DCIU) link. In addition to signaling links, analog or digital tie trunks interconnect each pair of switches. The tie trunks carry the actual voice traffic between switches.

DCS-CLUSTER

SYSTEM 85/	SYSTEM 85/
	TIE TRUNK
GENERIC 2	GENERIC 2
DCS TANDEM	DCS TANDEM
3XXXX	2XXXX
	DCIU
TIE	LINKS
TRUNK

PI/SCI

GATEWAY TO OTHER

DCS CLUSTERS, AN

ETN, OR OTHER

DEDICATED PRIVATE

NETWORK FACILITIES

LINK

SYSTEM

75 R1V2

ENDPOINT

4XXXX TIE

TIE TRUNK

TRUNK	5XXXX	SYSTEM 75/
	"DIMENSION"
		GENERIC 1
	SYSTEM
		DCS TANDEM
	FP8
		6XXXX
	NODE

Figure 6-1.Distributed Communications System (DCS) Cluster

6-1