AT&T DS1/DMi/ISDN-PRI Nonmetallic Cabling Options, 6DS1 Transmission and Cabling, DSX-1 T E DS1

3-6DS1 TRANSMISSION AND CABLING

The customer is responsibility for maintaining NCTEs. When purchasing service from the LEC, the customer must specify the DS1 framing and line-coding requirements.

For off-premises cabling, it is also possible to use any of the connection methods described for “On- Premises Cabling” as long as appropriate lightning and powerline cross-protection is provided.

Echo on voice channels must also be considered when a DS1 facility extends over long distances (that is, long round trip delays are encountered). Round trip delays of about 16-ms equate to about 100 miles through the public switched network or 800 miles in a private network. Each digital switch and each digital multiplexer in a path adds about 3-ms and 2-ms of delay respectively. Therefore, private network routes with several digital switches and digital multiplexer may need to use echo cancelers in path distances of less than 100 miles as shown in figure 3-2, On-PremisesMetallic-Cable Configurations. For a fee, AT&T Toll Offices can add echo cancelers.

	DSX-1	N C T E
DS1
		(NOTE)

655FT

MAXIMUM

	DSX-1	NOTE
DS1
		(NOTE)

655 FT

MAXIMUM

PROTECTION

CIRCUIT

REPEATERED

DS1 LINE

PROTECTION

CIRCUIT

NOTE: Use of the office repeater is optional depending on the distance to the first T1 repeater (unless it is needed to supply loop power).

Figure 3-2.Off-Premises Metallic Cable Configuration

NONMETALLIC CABLING OPTIONS

Many alternatives to DS1 metallic transmission facilities exist. Some of these include systems that transmit a DS1 signal on light-guide fiber, microwaves, infrared, and radio waves. All AT&T network distribution systems (NDS) products are compatible. Other systems should be compatible with System 75 and System 85 DS1s as long as the following conditions are met: