Span Powering Three Repeaters - ADTRAN HDSL4 Installation And Maintenance Manual

HDSL4 Deployment Guidelines

Span Powering Three Repeaters

An ADTRAN HDSL4 circuit can power three elements only. If three
repeaters are utilized in the circuit, the locally powered H4TU-R
(P/N 1223424L2, CLEI T1L83Z3C_ _ or later) must be utilized.
HDSL4 circuits utilizing three repeaters have different resistance
budget requirements. These requirements are provided separate
from the two-repeater support calculations. (DSL Assistant, ver-
sions 3.4 and prior, have no provision for three-repeater circuits.)
Under unusual circumstances, there may be extremely long loops for which three repeaters
will be required. The standards-based –190 VDC power supply can not span power all three
repeaters plus a span-powered remote. In this long-reach application, the DC resistances of
the individual segments between the Central Office and the third repeater must be within
limits similar to those described on the previous page.
The DC resistance graph for the three-repeater circuit (with locally powered remote) is shown
in Figure 55.
The procedure for utilizing this graph is identical to that described for
Span Powering Two Repeaters"
The greatest overall reach can be achieved by shortening the first segment, which reduces first
segment resistance, thus allowing the subsequent segments to span further.
The loop attenuation requirements for all of the segments beyond the first repeater are
identical since the modulation on those loops is identical.
60
HDSL4 for General Distribution Installation and Maintenance Practice
NOTE
NOTE
on page 58.
"Resistance Budget,
61223HDSL4L2-5C