Aethra d2001 nx ユーザーズマニュアル
USER’S MANUAL
ISDN TESTER AND ANALYZER D2001
NX
6
To send another tone (next), in case of ‘Sweep Time:
Manual’.
Manual’.
6
In order to send the next tone, in case Freq.start is equal
to Freq.stop.
to Freq.stop.
6
In order to send the previous tone, in case Freq.start is
equal to Freq.stop.
equal to Freq.stop.
The test does not provide specific results, the results page displays besides
frequency values transmitted and relative level, all ‘telephonic’ data available on the
line like in MAKE A CALL test.
frequency values transmitted and relative level, all ‘telephonic’ data available on the
line like in MAKE A CALL test.
3.6. BER test
The most used way to verify the transmission quality of a data connection, is
performing a BER (BIT ERROR RATE) test. In order to perform this test , the device
sends a sequence of pseudorandom bits (PRBS) on line and measures the error bits
ratio (BER) as the number of wrong bits received divided by the total number of bits
transmitted. The final result, is then estimated according to absolute parameters or
weighed according to the standard G.821.
performing a BER (BIT ERROR RATE) test. In order to perform this test , the device
sends a sequence of pseudorandom bits (PRBS) on line and measures the error bits
ratio (BER) as the number of wrong bits received divided by the total number of bits
transmitted. The final result, is then estimated according to absolute parameters or
weighed according to the standard G.821.
The test may be carried out in presence of an ISDN connection with signalling
protocol (e.g. E-DSS1), but also in leased data connection with several linking
technologies.
protocol (e.g. E-DSS1), but also in leased data connection with several linking
technologies.
Some of the parameters concerning the test have to be configured according to the
type of connection under verification.
type of connection under verification.
The final results instead, can be estimated in the same way a part from the type of
access.
access.
Various types of test may be performed in order to verify the BER on a line, the most
common are:
common are:
• Autocall
• Loop
• End-to-end
• Loop
• End-to-end
The ‘Autocall’ mode expects the use of only one testing device, this carries out a call
toward himself by using ISDN connections with signalling protocol over D channel. In
this way it is possible to check the quality of line up to the local exchange. This is the
typical test to carry out in first installation phase.
toward himself by using ISDN connections with signalling protocol over D channel. In
this way it is possible to check the quality of line up to the local exchange. This is the
typical test to carry out in first installation phase.
CHAPTER 3 - PERFORMING A MANUAL TEST
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