Loopback Operation; Generic Loopback Commands - ADC PAIRGAIN HiGain HDSL2 Manual

Testing
L O
OOPBACK PERATION
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
Loopback commands can be initiated by:
• Selecting the loopback type using the MODE and SEL buttons on the H2TU-C front panel (or the Manual
Loopback button on the H2TU-R)
•
Selecting the loopback type from the Monitor menu when connected to the craft port of the H2TU-C or
H2TU-R
•
Entering the loopback code into the test equipment connected to the H2TU-C or H2TU-R
HiGain HDSL2 only supports one active loopback; however, SmartJack loopback can be
present along with one other network loopback.

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. HiGain HDSL2 also supports NRGx regenerator loopbacks to the network and CRGx regenerator
loopbacks towards the customer. TLOS is a logic loopback caused by loss of the DS1 input from the CI.
Figure 25 summarizes the available loopbacks in the system, and
HDSL2 generic loopback commands. See
when using the GNLB mode.
48
"Special Loopback Commands" on page
"GNLB Test Procedures" on page 52
Figure 25. Loopback Summary
April 21, 2000
152-231-115-03, Revision 03
Table 21 on page
50) and the following
Table 22 on page 54)
Table 23 on page
Table 21 on page 49 summarizes the HiGain
for the test procedures that apply
49)
57)
H2TU-C-231 List 1E