ADTRAN ISU 128 - Manual (Page 37)

Chapter 5. Testing
22 ISU 128 User Manual 61202.029L2-1
DDS+V54 Accept
The ISU 128 responds to both DSU Latching Loopback commands (leased line
mode only) and V.54 loopback commands.
The ISU must be optioned for Clear Channel operation for DSU Latching and V.54
loopback commands to take effect.
Near-End Block Errors/Far-End Block Errors (NEBE/FEBE)
NEBE/FEBE allows the user to determine the quality of the network connec-
tion by viewing the number of near-end (NEBE) and far-end (FEBE) block er-
rors occurring on the ISDN interface. A large or incrementing count indicates
problems with network equipment. An incrementing or large count of NEBEs
indicates problems from the switch to the terminal adapter. An incrementing
or large count of FEBEs indicates problems in the direction from the terminal
adapter to the switch.
Software Version
Software Ver displays the software version and checksum in use on the ISU
128.
Press Cancel to exit any of these options.