ADC H2TU-C-388 Manual Do Utilizador

HiGain 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 

) and the following 

command tables:

Addressable Repeater Loopback commands: A1LB, A2LB, A5LB (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 (exceptions are COLB, DxLB, and RULB) into the test equipment connected to 
the H2TU-C or H2TU-R

The HiGain 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 system responds. TLOS 
is a logic loopback caused by loss of the DS1 input from the CI.

 summarizes the available loopbacks in the system, and 

 summarizes the HiGain 

generic loopback commands. See 

 for the test procedures that apply when 

using the GNLB mode.

Network

Customer
Premises

Activate loopback using
one of the following:

• MODE/SEL pushbuttons
• Maintenance Terminal
• Test Set

Activate loopback using
one of the following:

• LBK pushbutton
• Maintenance Terminal
• Test Set

NLOC

NREM
SMJK
TLOS

CREM

CLOC