2
Section 61245001L7-5, Issue 1
61245.001L7-5A
This HTU-C works with multiple list versions of the HDSL
unit remote end (HTU-R) and HDSL range extender
(HRE) as listed below:
• 1244041L2, Low Voltage T400 HRE
• 1244042L1, Low Voltage 819A HRE
• 1244044L1, Low Voltage 439 HRE
• 1245021L1, Low Voltage HTU-R T200 CP
• 1245022L1, Low Voltage HTU-R SA
• 1245026L1, Low Voltage HTU-R CI
The Low Voltage HTU-C can be deployed in circuits
consisting of one HTU-C and one HTU-R. When deployment
requires the HDSL Range Extender, the Low Voltage
HTU-C can be deployed with one Low Voltage HRE (T400
or 819A) and one Low Voltage HTU-R.
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 HDSL Transceiver Unit Remote end (HTU-R).
Each subsystem carries half of the total bandwidth along
with a small amount of overhead used for maintenance
and performance monitoring.
System power and alarm bus connections are made
through the backplane of the 220 shelf. DSX-1 and HDSL
signals are connected through the wire-wrap pins or the 50
pin shelf connectors related to each individual slot.
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 E220/220 Low Voltage HTU-C uses a DC-to-DC
converter to derive its internal logic and span powering
voltages from the -48 VDC office supply. The E220/220
Low Voltage HTU-C can span power HREs and HTU-Rs
as listed above. When used with Low Voltage HREs and
HTU-Rs, the HTU-C can span power the Low Voltage
HTU-R and Low Voltage HRE at less than –140 VDC.
Span powering voltages meet all requirements of Class
A3 voltages as specified by Bellcore GR-1089-CORE.
Revision History
This is the first issue of this practice. In subsequent
issues, changes will be summarized in this paragraph.
2.
INSTALLATION
After unpacking the unit, 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).
The E220/220 Low Voltage HTU-C plugs directly into
standard 220 office repeater shelves. These include
Kentrox T-Term 220, Wescom 34220 and 34230, Lynch
303MA30 as well as the ADTRAN E220 Shelf and the
ADTRAN E220 RP Shelf. No installation wiring is required.
One six-position rotary switch (RSW) and a five-position
dipswitch pack (SW1) accessible from the faceplate of
the unit are used to configure the mode of operation.
Figure 1 shows the location of these switches.
A definition of each switch is shown in Tables A and B.
Configuration may be performed by manually selecting
each option switch, or alternatively, may be performed
using the RS-232 craft access port. Manual configuration
can be performed after installing the unit into the shelf.
When the unit is powered up, changing a single faceplate
switch only affects that single parameter. When the unit
is powered down, changing a single faceplate switch
causes a global reset to revert back to all faceplate
switch settings.
Craft interface allows configuration of DS0
Blocking and additional loopback timeout
settings.
Faceplate Indicators
The HTU-C has five faceplate LEDs which indicate
operational status. Table C defines these LEDs.
Table A. Front Panel Rotary Switch Option Settings
1
Switch
Function
Description
RSW
DSX-1 Line Build-Out .... This rotary switch is used to select operation of the line build-out equalizer in series with the DSX-1 output.
EXT ................................ Selects external line build-out
2
0 ................................. Line length from 0-133 feet of ABAM cable
133 ................................. Line length from 133-266 feet of ABAM cable
266 ................................. Line length from 266-399 feet of ABAM cable
399 ................................. Line length from 399-533 feet of ABAM cable
533 ................................. Line length from 533-655 feet of ABAM cable
1
The HTU-C transfers the local configuration to the HTU-R when circuit synchronization is achieved. The HTU-R then sets its configuration
to match the HTU-C.
2
If external line build-out is selected, the signal transmitted by the HTU-C is a 12V p-p signal. This must be considered when measuring the
signal at the DSX EQ faceplate Bantam jack. The signal may appear hotter than it should be.
