Adtran ISU 128 User Manual

Chapter 5. Testing

ISU 128 User Manual

61202.029L2-1

 causes the ISU DTE port to loop back toward user equipment.  

This allows performance of a bit error rate test (BERT) between the ISU 128 
and the end user equipment to verify proper cable connection.

 
Loopback Network 

forces the ISU 128 to loopback both the B1 and B2 chan-

nels toward the network.  This can be used to allow a far-end user to perform 
a BERT all the way through the network.

 allows data to loopback toward the network after passing 

through a selected protocol such as T-Link or BONDING.  See Figure 5-3 for 
loopback points.

1=STATUS
2=TEST
3=CONFIG
4=DIAL

1=Loopback DTE

2=Loopback Netw.

3=Loopback Proto

4=Loopback Remote

5=Test Remote

6=Lpbk Disable

7=NEBE/FEBE

0=Software Ver

1=No Rem Lpbks

2=DDS Accepted

3=V54 Accepted

4=DDS + V54 Accept

NET

IFC

RATE 

ADAPTION

DTE  

IFC

NETWORK

Network

Protocol

DTE

DTE