AT&T 7500 series manual DCS Signaling Link Connections, Equipment Distance Limitation, Mtdm/Mpdm

6-8DISTRIBUTED COMMUNICATIONS SYSTEM (DCS)

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DCS SIGNALING LINK CONNECTIONS

Many variables influence how the signaling channel on one DCS node is connected to the signaling channel on another DCS node. Chief among these variables is the types of communications systems being connected. For example, the System 75 and Generic 1 communications systems are connected differently to other System 75s and Generic 1s than they are to System 85s and Generic 2s. Furthermore, within the constraints imposed by the communications systems being connected are other constraints imposed by the distance that the transmission must travel, the availability of digital trunks, the cost, etc. All these variables must be considered when you decide how to connect the DCS signaling links. Illustrated next are the types of connections possible given the types of communications systems being connected.

The connections are classified as long haul and short haul. Long haul connections have virtually no distance limitations. Distance limitations on short haul connections are established by the types of data sets/modules used. When you choose to use a particular type of connection, you should consider the following distance limitations:

Equipment	Distance Limitation
RS-232/RS-449 Link	50 ft
Isolating Data Interface (IDI)	400 ft.
Data Service Unit	2000 ft.
MTDM/MPDM	3500 ft.
DCP Link	5000 ft.

System 75 or Generic 1 (G1) to System 75 or G1

PI

TN764

(DIGITAL LINE)

TN760

(TIE TRUNK)

TN722

OR TN767

(DS1)

SYSTEM 75/G1

	SIGNALING CHANNEL
DCP	DSU	MTDM	DCP
MTDM
	DSU
	ANALOG OR DS1 VOICE CHANNEL

PI

TN764

(DIGITAL LINE)

TN760

(TIE TRUNK)

TN722

OR TN767

(DS1)

SYSTEM 75/G1

Figure 6-6.Short Haul Analog Signaling: System 75/G1 to System 75/G1 Via DSU