Specifications

Chapter 5 Troubleshooting and Diagnostics Installation and Operation Manual
5-4 Configuration for Diagnostic Tests ASMi-52CD Ver. 1.0
Running Loopback Tests
The purpose of a loopback test is to determine the source of a break in the data
flow.
Only one loopback can be activated at a time, either local or remote.
When a test is active, no other test can be activated for the current modem.
Running the Local Analog Loopback
The local analog loopback (LLB) checks the performance of the local ASMi-52CD
modem, the local DTE and connection between them (see
Figure 5-2 ).
Local
DTE
Data
ASMi-52CD
Data
Clock
Clock
Line
Interface
Glue
Logic
Transmit
Receive
Figure 5-2. Local Analog Loopback
Before running the local analog loopback on ASMi-52CD units perform the
following steps:
• ASMi-52CD with serial DTE interface
 Configure testing equipment (for example, RAD’s HBT) to internal clock
and 2048 kbps baud rate.
• ASMi-52CD with E1 DTE interface
 When operating in the framed mode, configure the E1 testing equipment
to internal clock, G732N framing and assign 31 timeslots to carry data,
timeslot 0 – transparent.
 When operating in the unframed mode, configure the E1 testing
equipment to the unframed mode.
 To run the local analog loopback test:
• In the Modem Diagnostics screen, move the cursor to LOOP & BERT field by
pressing <Tab> and select ANA by typing <f> or <b>, and pressing <Tab>
again.
Note