Description; Table 1. Hdsl Compatibility - ADTRAN HDSL DDM+ HTU-C Installation And Maintenance Practice

HDSL DDM+ Transceiver Unit for Central Office Installation and Maintenance Practice

DESCRIPTION

DSX-1 signals are provided to and from the network while 2B1Q HDSL signals are provided to
the local loop. The DDM+ HTU-C works in conjunction with the ADTRAN HDSL Transceiver
Unit for the Remote end (HTU-R) and HDSL Range Extender (HRE) to provide a DS1 service up
to 36,000 feet on the local loop.
The DDM+ HTU-C works with multiple list versions of the HTU-R and HRE as listed below in
Table 1.
Part Numbers
1245024L1
1246026Lx
1247024L1
1247026Lx
1246041L1
1246045L1
1247041L1
1247045L1
x = any number
The DDM+ HTU-C can be deployed in circuits consisting of one HTU-C and one HTU-R. When
deployment requires the HRE, the DDM+ HTU-C can be deployed with one or two HREs and
one HTU-R.
The HDSL local loop operates as two independent subsystems each operating over a single
twisted pair. The DDM+ HTU-C communicates over these two twisted pairs to the HTU-R.
Each subsystem carries half of the total bandwidth along with a small amount of overhead
used for maintenance and performance monitoring related functions.
System power and alarm bus connections are made through the backplane of the DDM+ shelf.
DSX-1 and HDSL signals are connected through the wire-wrap pins related to each individual
slot located on the rear of the shelf.
The DDM+ HTU-C uses a DC-to-DC converter to derive its internal logic and span powering
voltages from the –48 VDC office supply.
The DDM+ HTU-C can span power HREs and HTU-Rs as listed above. When used with HREs and
HTU-Rs, the DDM+ HTU-C can be configured to span power the HTU-R and HRE at –190 VDC
(for applications requiring two HREs and an HTU-R). Span powering voltages meet all require-
ments for Class A2 voltages of by Bellcore GR-1089-CORE.
The DDM+ HTU-C contains an onboard fuse. If a fuse opens, it supplies a –48 VDC voltage to
the fuse alarm bus and turns all front panel indicators off. These fuses are not designed to be
field replaceable.
2

Table 1. HDSL Compatibility

Description
T400 HTU-R with Local Power Option
6th Gen HTU-R
7th Gen HTU-R, Local Power
7th Gen HTU-R, Span Power
6th Gen T200 HRE
6th Gen 239 HRE
7th Gen T200 HRE
7th Gen 239 HRE
61247003L6-5A