Loopback Operation; Generic Loopback Commands; Loopback Summary - ADC Campus-RS Remote User Manual

Loopback Operation

L
OOPBACK
HiGain HDSL2 has a family of loopback options for analyzing circuit functionality. The loopback signal is
transmitted and returned to the sending device for comparison. This allows you to verify the integrity of the
HDSL2 channels to the H2TU-C, the H2TU-C DSX-1 interface, and the DS1 channels to the customer. Loopback
options include:
• Generic Loopback (GNLB) options, including the SmartJack (SMJK) option (see
• Special Loopback (SPLB) options (see
command tables:
–
Addressable Repeater Loopback command: A2LB (see
–
Addressable Repeater Loopback commands: A3LB, A4LB (see
Loopbacks can be initiated by:
•
Selecting the loopback type using the MODE and SEL buttons on the H2TU-C front panel
• Selecting the NREM-CLOC dual loopback using the LBK button on the H2TU-R front panel
•
Selecting the loopback type from the Monitor screen when connected to the H2TU-C or H2TU-R craft port
• Entering the loopback code into the test set connected to the craft port of the H2TU-C or H2TU-R
The H2TU-R-402 List 4E performs a metallic loopback self test when looping up an NREM or
SMJK loopback.
HiGain HDSL2 supports multiple loopbacks, but a single loopback is the preferred method.

Generic Loopback Commands

The HiGain HDSL2 Generic Loopback (GNLB) commands allow you to use inband codes to loop up either
NLOC (4-in-7) or NREM (3-in-7) towards the network. In addition, these inband codes loop up CREM (6-in-7)
or CLOC (5-in-7) towards the customer. Either loopup condition can be terminated (looped down) with the 3-in-5,
SMJK loopdown code. All inband codes must be present for at least 5 seconds before the HiGain HDSL2 system
responds. TLOS is a logic loopback caused by loss of the DS1 input from the CI.
Figure 21 summarizes the available loopbacks in the system, and
HDSL2 generic loopback commands. See
when using the GNLB mode.
Activate loopback using
one of the following:
• MODE/SEL pushbuttons
• Maintenance Terminal
• Test Set
24
O
PERATION
"Special Loopback Commands" on page
"GNLB Test Procedures" on page 26
NLOC CREM
H2TU-C
Network
Figure 21. Loopback Summary
June 16, 2000
Table 11 on page 28)
Table 12 on page
Table 10 on page 25
for the test procedures that apply
Activate loopback using
one of the following:
• LBK pushbutton
NREM
• Maintenance Terminal
SMJK CLOC
• Test Set
TLOS
H2TU-R
Customer
Premises
152-402-145-02, Issue 2
Table 10 on page 25)
26) and the following
30)
summarizes the HiGain
H2TU-R-402