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Chapter 2 Data Communications Testing
Data communications testing features and capabilities
Data communications testing
Data communications testing involves specifying the settings required to perform the
test, connecting to the interface you are testing, starting the test, and then observing
test results. Using the MSAM, you can perform BER analysis of a variety of data
communications interfaces, measure round trip delay, and troubleshoot timing issues
using the test results provided.
Before you begin testing, be certain to review the basic concepts included in
Chapter 1 "Basic Testing"
The MSAM provides the tools you need to test and verify network connectivity and
performance for a variety of data communication interfaces. Using the instrument, you
can perform BER analysis of the interfaces to verify error free performance and trans-
mission, and emulate signals to verify proper initialization of the interfaces.
Features and capabilities of the MSAM with an HS Datacom PIM include the following:
•
Self Loop—Before you start testing, you can perform a self loop to validate the
unit and the selected test interface on the instrument.
•
User specified test intervals—You can set up the instrument to run a test continu-
ously, or to run a test for a specific timed interval lasting up to seven days.
•
End-to-End Testing—You can analyze the performance of an entire digital link in
both directions, allowing you to isolate problems to a specific direction.
•
BER testing—You can BER test a variety of data communication interfaces to
verify error free performance and transmission by transmitting ANSI, ITU, user
programmable, and long user patterns (LUP). You can also specify the BERT
pattern sync loss criteria and the action to be taken upon loss of pattern sync.
•
Sync loss criteria—When you select a BER pattern, you can specify sync loss
criteria to control the unit's sensitivity in declaring loss of synchronization, and
indicate when the unit should attempt to regain synchronization.
•
Asynchronous timing—You can set up the instrument to use asynchronous timing,
and then select the internal synthesizer or an external clock (using the BNC
connector on the MSAM) as the clock source.
•
Synchronous timing—You can set up the instrument to use synchronous timing,
and then specify a valid clock source for the interface. Possible sources include
the internal synthesizer or an external clock. You can also recover timing from the
received data stream.
•
Flow control—You can set up the instrument to use in band flow control by trans-
mitting XON/XOFF characters, or out of band (hardware) flow control by inter-
preting signals from selected leads on the instrument and its link partner.
•
Round trip delay measurement—Using the instrument, you can transmit and loop
back a DELAY pattern, and then measure the time it takes to receive the pattern.
Specifying interface settings
The first step in testing a data communications interface is to select the interface you
are testing and the emulation mode for the instrument. If applicable, you also specify
Page 12
features and capabilities
Data Communications and Diphase Testing Manual
21148872, Rev. 002
January 2016
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Table of Contents
Troubleshooting
