Installation - ADTRAN DDM Plus HTU-C Installation And Maintenance Manual

The HTU-C can be deployed in circuits consisting
of one HTU-C and one HTU-R. When deployment
requires the HRE, the HTU-C can be deployed with
one Low Voltage HRE (T400, 239, 439, or 819A)
and one Low Voltage HTU-R.
NOTE
When deployment requires the use of two HREs,
the HTU-C can be deployed with two
T400 HREs (P/N 1244041L2) and one HTU-R
(P/N 1245021L1 or 1245026LX).
The HDSL local loop operates as two independent
subsystems each operating over a single twisted
pair. The 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 Plus 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 Plus 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
Plus HTU-C can span power HREs and HTU-Rs as
listed above. When used with HREs and HTU-Rs,
the HTU-C can be configured to span power the
Low Voltage HTU-R and Low Voltage HRE at
either less than -140 Vdc or -190 Vdc (for
applications requiring two HREs and an HTU-R).
Span powering voltages meet all requirements of
Class A2 voltages as specified by Bellcore
GR-1089-CORE.
The HTU-C contains onboard fuses. If a fuse
opens, it supplies a -48 Vdc voltage to the fuse
alarm bus and all front panel indicators will be off.
These fuses are not designed to be field replaceable.
The DDM Plus HTU-C uses a DC-to-DC converter
to derive its internal logic and span powering
voltages from the -48 Vdc office supply.
2
Revision History
This practice has been reissued to incorporate a
CLEI code change.
Electrical Code Compliance
Table 1 shows the UL/CUL Telecommunications Codes
for the DDM Plus HTU-C. The DDM Plus HTU-C
complies with the requirements covered under UL
1459 third edition and is intended to be installed in an
enclosure with an Installation Code (IC) of "B" or "E."
• This product is intended for installation
in RESTRICTED ACCESS
LOCATIONS only.
• Input current at maximun load is 1 A at -
48 Vdc.
• Maximum output at overcurrent
condition is 160 mA at -188 Vdc.
Table 1. Telecommunications Codes
Code
Installation Code (IC)
Telecommunication Code (TC)
Power Code (PC)

2. INSTALLATION

After unpacking the unit, immediately inspect it for
possible shipping damage. If damage is discovered,
file a claim immediately with the carrier, then
contact ADTRAN Customer Service (see subsection
10 of this practice).
The DDM Plus HTU-C plugs directly into the
AT&T DDM Plus shelf. The unit may be plugged
into any of the 28 numbered slots in this shelf. No
installation wiring is required.
Section 61245003L6-5, Issue 5
NOTE
Input
A
–
F
C A U T I O N ! C A U T I O N
SUBJECT TO ELECTROSTATIC DAMAGE
OR DECREASE IN RELIABILITY.
HANDLING PRECAUTIONS REQUIRED.
61245003L6-5E
Output
–
X
C