4
61190852L2-5, Issue 3
61190852L2-5C
Installing Line Units
The following steps describe how to install an HTU-C
line unit into the HDSL CO Installation Kit, connect
the line unit to the HDSL circuit, and remove the line
unit.
1. Locate the slot to install the HTU-C on the HDSL
Central Office Installation Kit.
NOTE
Before handling line units, connect the HDSL
Installation Kit to ground and connect the ESD
wrist strap to the installation kit.
2. Grasp the HTU-C by its front panel and align it
with the guides in the slot. Slide it into the slot
until it seats firmly with the connector at the rear.
3. Connect the HTU-C to the HDSL circuit by
installing a cable between the LP1 and LP2
signal jacks on the HDSL Installation Kit and the
HDSL circuit’s loop 1 and loop 2 twisted pairs.
Maintain signal polarity by observing the color
coding of the cable ends. Connect the CO LP1/
LP2 signal jacks to the loop 1 and loop 2 twisted
pairs, respectively, going to the remote end of the
HDSL circuit.
4. To remove an HTU-C, remove the patch cord
connecting the HTU-C to the HDSL circuit.
Pull the ejector lever on the bottom of the
HTU-C, or grasp it by its front panel and gently
pull it from the slot, observing ESD precautions.
Installing Test Cables
The HDSL Installation Kit is connected to the HDSL
circuit by installing test cables between the installation
kit’s LP1 and LP2 signal jacks and the twisted pair or
twisted pairs that form the HDSL circuit.
The cables are attached depending on the installation
as follows:
• For a single-pair HDSL installation, use a test
cable with a single-bantam end and two alligator
clips. Insert the cable’s bantam end in the LP1
signal jack, and attach each alligator clip to one
of the wires in the twisted pair.
• For a two-pair HDSL installation, use a test cable
with a dual-bantam end and four alligator clips.
Insert the cable’s bantam end in the LP1/LP2
signal jacks, and attach each set of alligator clips
to the wires in the corresponding twisted-pair.
• For ADTRAN HDSL, the loops are insensitive to
tip-ring reversal. For other applications, such as
standard T1 testing, the following describes the
polarity of the test set. The bantam to alligator-
clip test cables in the HDSL Installation Kit
indicate tip-and-ring connectivity as follows:
– The alligator-clip cable ends are color-coded
red (tip) and green (ring) loop 1, yellow (tip)
and black (ring) loop 2.
– The sleeves on the alligator-clip cable ends
are labeled to match their corresponding
bantam end.
– When installing a test cable, maintain signal
polarity by matching the LP1/LP2 bantam
cable ends to the correct alligator-clip ends
(LP1 bantam to loop 1 alligator clips, and LP2
bantam to loop 2 alligator clips). It does not
matter which twisted-pair is considered loop 1
or loop 2 as long as the designations are
consistent. (See
Figure 6
).
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.
Figure 6. Test Cables
Loop 1
Loop 2
Red
Loop 1 (T)
Loop 1 (R)
Loop 2 (T)
Loop 2 (R)
Green
Yellow
Black
