LTPH-UM-1109-01, Issue 1

Testing

 

 

LOOPBACK OPERATION

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 Table 16 on page 44)

•Special Loopback (SPLB) options (see “Special Loopback Commands” on page 45) and the following command tables:

–Addressable Repeater Loopback commands: A1LB, A2LB, A5LB (see Table 17 on page 49)

–Addressable Repeater Loopback commands: A3LB, A4LB (see Table 18 on page 51)

Loopback commands can be initiated by:

•Selecting the loopback type using the MODE and SEL 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 (exceptions are COLB and RULB) into the test equipment connected to the H2TU-C-231 or H2TU-R.

Activate loopback using

 

 

 

 

 

 

 

 

 

 

 

 

 

Activate loopback using

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

one of the following:

 

 

 

 

 

 

 

 

 

 

 

 

 

one of the following:

• MODE/SEL pushbuttons

 

 

 

 

 

 

 

NREM

 

 

 

 

 

• LBK pushbutton

• Maintenance Terminal

 

NLOC

 

 

CREM

 

 

 

 

 

• Maintenance Terminal

 

 

 

SMJK

 

 

CLOC

• Test Set

 

 

 

 

 

• Test Set

 

 

 

 

 

 

 

TLOS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

H2TU-C

 

H2TU-R

 

 

 

 

 

 

 

Network

Customer

Premises

 

Figure 27. Loopback Summary

Generic Loopback Commands

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 HDSL2 system responds. TLOS is a logic loopback caused by loss of the DS1 input from the CI.

Figure 28 on page 48 summarizes the available loopbacks in the system, and Table 16 on this page summarizes the HiGain HDSL2 generic loopback commands.

H2TU-C-231 List 2

January 9, 2002

43