ADC HiGain H2TU-C-319 List 4E - Manual (Page 63)

LTPH-UM-1049-02, Issue 2 Testing
H2TU-C-319 List 4E January 9, 2002 55
L
OOPBACK
O
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) commands, including the SmartJack (SMJK) option (see Table 22 on page 56 )
• Special Loopback (SPLB) commands (see “Special Loopback Commands” on page 56 ) and the following
command tables:
– Addressable Repeater Loopback commands: A2LB (see Table 21 on page 52 )
– Addressable Repeater Loopback commands: A3LB, A4LB (see Table 24 on page 64 )
Loopback commands can be initiated by:
• Selecting the loopback type using the MODE and LBK pushbuttons on the H2TU-C front panel or the manual
loopback (LBK) pushbutton 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.
Figure 31. Loopback Summary
HiGain supports multiple loopbacks, but a single loopback is the preferred method.
Network
Customer
Premises
Activate loopback using
one of the following:
• Maintenance terminal
• Test set
• MODE/SEL pushbuttons
Activate loopback using
one of the following:
• Test set
• Loopback pushbutton
• Maintenance terminal
H2TU-C H2TU-R
NLOC
NREM
SMJK
TLOS
CREM CLOC