Section 150-611-100
Revision 02
Page 14
TABLE 3. HLU-611 TEST PROCEDURES FOR GNLB OPTION
Step
Action
1
Have the C.O. tester send the HRU (3 in 7) in-band loop-up code for five seconds. Observe that the HLU
displays the “NREM” message indicating an HRU loopback is in effect (see Figure 5).
2
Have the C.O. tester transmit a T1 test signal into the HLU and verify that the returned (looped) signal is
error free.
3
If the above test fails, have the C.O. tester transmit the (3 in 5) in-band loop-down code. Verify that the
HLU display returns to normal.
4
Have the C.O. tester send the HLU (4 in 7) in-band loop-up for five seconds. Observe that the HLU
displays the “NLOC” message indicating an HLU loopback is in effect.
5
Repeat step “2”. If the test passes, the problem is in the cable pair or the HRU. If it fails, the problem is
in the C.O. equipment.
6
The NREM, NLOC, CREM and CLOC loopbacks can also be initiated from the front panel of the HLU
with the MODE and SEL pushbuttons. See Paragraph 7.21 for details.
7
The HLU can be looped-up from the remote location (CREM) by issuing the 6 in 7 command at the HRU’s
DS1 input port.
8
The HRU can be looped-up from the remote location (CLOC) by issuing the 5 in 7 command at the HRU’s
DS1 input port.
