AT&T DS1/DMi/ISDN-PRI Telephone User Manual


 
3-4
DS1 TRANSMISSION AND CABLING
Because ANN11Ds, ANN11Es, TN722Bs, and TN767s contain components that suppress unwanted
emissions from a DS1, standard premises distribution system (PDS) cables may be used to
interconnect these interfaces. The PDS wiring may only be used when connecting directly between
System 75 and System 85 DS1s. Other equipment is not guaranteed to meet FCC emission
requirements when used with unshielded cable. Allowable PDS cables include the following cable
types or their electrical equivalents:
All 24-gauge PDS cable
26-gauge PDS cable of types ARTM, BKTA, or AFTW
NOTE: A 26-gauge cable has different distance limitations from 24-gauge cable. ANN11Cs
do not contain components that suppress unwanted emissions. Therefore, when an ANN11C
is used (either at one or both ends of a connection), PDS cables cannot be used. Shielded
twisted-pair cable (DCC-5/24-TSA) is required.
Between 1310 and 4310 Feet
When the distance between DS1s exceeds 1310 feet, repeaters are required to regenerate the signal.
If the total distance is less than 4310 feet, NCTEs containing office repeaters may be used at each
end of a DS1 facility as shown in figure 3-1-B, On-Premises Metallic-Cable Configurations.
Generally, the repeater module is ordered separately from the NCTE. The repeater module circuit is
then installed within the NCTE housing as a part of the installation process.
Office repeaters only regenerate signals that are received from the transmission line span. NCTEs
must be within 655 feet of their respective DS1 or the distance between the NCTEs should not exceed
3000 feet. Using NCTEs and office repeaters permits a total maximum distance of 4310 feet.
NCTEs must be powered by a DS1 line or an external DC power source. Each NCTE connects to its
respective DS1, DMI, or ISDN-PRI via a 15-pin D-connector on the rear of the NCTE.
NOTE: PDS cabling should not be used for connecting to or between NCTEs. For equipment
cabinet to NCTE connections, use DCC-5/24-TSA cables with appropriate connectors (such as
ED1E434-11, group 181, group 370, group 380 or the combination of group 380 and group 506
when connecting to a universal module) and applicable length.
Greater Than 4310 Feet
When distance between DS1s is greater than 4310 feet, line repeaters are required. Line repeaters
regenerate the signal for both the receive and transmit directions. NCTEs and their associated DC
power supplies (if necessary) are also required for this configuration. NCTEs are used to provide
power to the line repeaters over the line.
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 3-1-C, On-Premises Metallic-Cable
Configurations, shows this configuration.