Installation
150-412-107-03, Revision 03
10
November 19, 1999
HRU-412 List 7
L
OCAL
P
OWERING
When locally powered, the HRU-412 List 7 provides 15 mA (short loop) or
10 mA (long loop) metallic sealing current toward the HLUs and HRUs (all
models) over the two HDSL pairs. JP2, shown in
, allows the sealing
current to be enabled or disabled. To enable the sealing current, connect JP2
across both terminals. To disable the sealing current, remove the jumper from
the inner terminal and attach it to the outer terminal. The factory default
setting is disabled.
I
NSTALLATION
T
EST
Perform the following procedure to test the HRU-412 List 7.
1
Press the loopback button (see Figure 2 for the location of this button) for
at least five seconds.
Verify that the LB NET LED is steady green, indicating that the
HRU-412 is in a digital (NREM) loopback state. If possible, verify that
the HLU front panel displays NREM.
2
Have the CO transmit a T1 test signal to the HLU.
Measure the return (loop) signal to verify it is error free. If the signal is
not error free, remove the HRU-412 from loopback by pressing the
loopback button for five seconds. The LB NET LED should be off.
3
Have the CO send the HLU 4-in-7 in-band loopup (NLOC) for five
seconds.
Verify that the HLU front panel displays NLOC.
4
Repeat step 2.
If the test passes, a problem exists in the cable pair or in the HRU-412. If
the test fails, the problem is at the CO.
5
Check that the proper ports are in use for the HDSL and DS1 pair by
using an ohm-meter to verify that the HDSL ports have a 180 k
transmit
to receive resistive signature and that the DS1 ports have a 15
transmit
to receive resistive signature.
Measure the return (loop) signal to verify it is error free.
6
If using an external NID, set the I-CPE switch (located on the back panel
of the HRU-412; see Figure 3) to 60 mA and verify the NID is under
power. Check that the voltage across the front panel test points
(60 mA MON) measure between 55 mV and 65 mV.
7
Enable the sealing current option (JP2 connected). Use a mili-amp meter
to verify transmit or receive current in either HDSL pair.
