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Section 150-232-100
Revision 01
Page 53
4. TESTING
4.01 Table 16 through Table 21 provide step-by-step test procedures for the HLU-232 List 1D as a function of the
loopback option selected. These procedures allow verification of the integrity of the HDSL channels at every module
location as well as the DS1 channels to the customer and the local DSX-1 interface.
4.02 The HLU-232 List 1D 4-character front panel display has many useful system diagnostic messages; which are
listed in Table 22. The display turns on when power is initially applied to the HLU-232 List 1D. In order to conserve
power, it only remains on for four minutes if neither the MODE nor SEL buttons are pressed. The use of either
button activates the 4-character display and restarts the 4-minute power-control timer.
4.03 If trouble is encountered on the HLU-232 List 1D DSX-1 interface, verify that the HLU-232 List 1D is properly
seated in the HSA-232 adapter, and the HSA-232 is properly seated in the 220-shelf. Also, verify that the HLU-232
List 1D internal equalizer is set to EXT for driving external equalizers or to the correct distance range per Table 2 for
internal equalization. All installations should be set to the largest value that does not exceed the distance from the
DSX-1 to the shelf.
4.04 The transmit and receive T1 DSX-1 ports have splitting access and bridging miniature 210-series jacks as
shown in Figure 3. Connecting one cable between the two bridging jacks and another between the two SPAN jacks
splits the XMT and RCV and creates metallic loopbacks towards both the DSX-1 and the HLU-232 List 1D. If plugs
are inserted into both SPAN jacks, the BRG jacks can be used to send and receive test patterns towards the DSX-1.