ATT Definity Addendum 1 For Ds1, Dmi, Isdn Pri Instructions Manual

DS1 TRANSMISSION AND CABLING3-7
Direct — Under 1310 Feet
If two DS1s are separated by no more than 1310 feet (or no more than 655 feet to the same DSX-1
cross-connect point), then they may be connected directly without the need of additional equipment.
The cross-connect point is generally not required and the connection may consist of a single continuous
1310 foot cable. Figure 3-2-A, On-Premises Metallic-Cable Configurations, shows this configuration.½
Because ANN11Ds, ANN11Es, TN722Bs, and TN767s...

3-8DS1 TRANSMISSION AND CABLING
Line repeaters may be placed up to 3000 feet from the NCTEs, and line repeaters may be spaced up to
6000 feet apart. NCTEs must still be within 655 feet of their respective DS1s. When using two line
repeaters, DS1s can be up to 13,310 feet apart. This distance may be extended in increments of 6000
feet by using additional line repeaters. Figure 3-2-C, On-Premises Metallic-Cable Configurations, shows½
this configuration.
DS1DS1
655 FT655 FT
MAXIMUM
MAXIMUM
DSX-1 PHANTOM...

DS1 TRANSMISSION AND CABLING3-9
Off-Premises Cabling
When DS1s reside in different locations, they are typically connected via a transmission facility (such as
a metallic cable configuration) that is leased from the LEC. This facility usually consists of a line and
T1 repeater combination. The customer premises equipment interfaces to a DS1 network facility (T1
line) via NCTEs.
The customer is responsibility for maintaining NCTEs. When purchasing service from the LEC, the
customer must specify the...

3-10DS1 TRANSMISSION AND CABLING
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:½
lThe transmission system connects to a DS1 via a DSX-1 cross-connect
lThe...

DS1 TRANSMISSION AND CABLING3-11
DS1/DMI
OR D4
CHANNEL
BANKDSX-1
DSX-1DS1/DMI
OR D4
CHANNEL
BANKCEMDSX-1ANY DS1
TRANSMISSION
MEDIADSX-1
CEM
DS1/DMI
OR D4
CHANNEL
BANKDSX-1DSX-1DS1/DMI
OR D4
CHANNEL
BANK
A. CEM ONLY
DS1/DMI
OR D4
CHANNEL
BANKDSX-1
CDM
CDM
DSX-1DS1/DMI
OR D4
CHANNEL
BANK DSX-1
ANY DS1TRANSMISSIONMEDIADSX-1DEDICATED
CHANNEL
APPLICATIONSCHANNEL
UNITSCHANNEL
UNITSDEDICATED
CHANNEL
APPLICATIONS
B. CDM ONLY
DS1/DMI
OR D4
CHANNEL
BANK
DSX-1
ANY DS1
TRANSMISSION
MEDIA
DSX-1DS1/DMI
OR D4
CHANNEL...

3-12DS1 TRANSMISSION AND CABLING
LINE EQUALIZER AND COMPENSATION SETTINGS
The Generic 1 and Generic 2 DS1 circuit packs generate a signal that is preequalized. Preequalized
means that the bipolar signal is shaped so that when it reaches the cable end it conforms to the DSX-1
power specification.½
½
System 85 Traditional Modules½
Traditional modules may be equipped with the ANN11 and ANN35 circuit packs. Preequalization is
provided by properly setting the three equalizer switches, on the circuit packs....

SYNCHRONIZATION OF DIGITAL FACILITIES5-29
CONCLUSIONS ON SYNCHRONIZATION
Make no assumptions regarding synchronization. Reverify items such as the availability of a
synchronization source, the clock stratum, and compatibility of every T1 span. The best guarantee is
written confirmation that the local exchange carrier, AT&T Communications, or other vendor will either
synchronize to a System 75, System 85, Generic 1, Generic 2, or provide an appropriate synchronization
reference.½
Develop a diagram showing...

5-30SYNCHRONIZATION OF DIGITAL FACILITIES
l
lSince the D4-channel bank (or equivalent) at the far end will be timed to the signal received from a
DS1, no slips should occur on a line-only mode DS1 facility. Because of this, slip counts from
line-only mode DS1s should not be used to determine the health of a clock reference (that is, they
would tend to make the reference appear to be in better condition than it may be).½
Line-only mode DS1s should not be used as system clock references unless it is known...

SYNCHRONIZATION OF DIGITAL FACILITIES5-31
Trunk-Mode Interface (ISDN-PRI + Robbed Bit) (TN767)
Since it is expected that a trunk mode DS1 would terminate at a class-5 or higher CO or at another
switch, the trunk interface should be suitable for use as a primary or secondary clock reference (or to be
the timing master for another switch).*
The slip count provided by the interface should also be used in the process of choosing a healthy clock
reference. However, when the interface terminates on a...

5-32SYNCHRONIZATION OF DIGITAL FACILITIES
ADDENDUM 1 (December 1990) to 555-025-101, Issue 4