Patton electronic 2720 user manual BIT Error Rate V.52 Diagnostics, Qrss

2.Perform a bit error rate test (BERT) using the internal V.52 generator (as described in Section 5.3), or using a separate BER Tester. If the BER test indicates a fault, and the Local Line Loopback test was successful for both NetLink™s, you may have a problem with the twisted pair line connection.

5.2.3CSU Loop

The NetLink-T1™ also responds to central office initiated loop com- mands. The NetLink-T1™ will implement the “loop up” command when it recognizes the pattern “10000” in the data stream for a mini- mum of 5 seconds. The “loop down” command is implemented by the pattern “100” in the data stream for a minimum of 5 seconds.

When operating in ESF framing mode, loopback commands are issued via the Facility Data Link (FDL). The line loop message will cause a loop back before data enters the framer portion of the CSU. The payload loop message will cause the NetLink-T1™ to loop data after the framer portion of the CSU.

The NetLink-T1™ will respond to Universal Loopback De-activate to clear all central office loops.

5.3 BIT ERROR RATE (V.52) DIAGNOSTICS

The NetLink-T1™ offers three V.52 Bit Error Rate (BER) test pat- terns. These test patterns may be invoked along with the LAL and RDL tests to evaluate the unit(s) and the communication links.

When a 511, 2047, or QRSS test is invoked, the NetLink-T1™ generates a pseudo-random bit pattern of 511 bits, 2047 bits or 220 bits, respectively, using a mathematical polynomial. The receiving NetLink- T1™ then decodes the received bits using the same polyno- mial. If the received bits match the agreed upon pseudo-random pat- tern, then the NetLink-T1™(s) and the communication link(s) are func- tioning properly.

511	Initiates a built-in 511 bit pseudo-random
	pattern generator and detector.
2047	Initiates a built-in 2047 bit pseudo-random
	pattern generator and detector.
QRSS	Initiates a built-in 220 bit pseudo-random
	pattern generator and detector.

To perform a V.52 test, follow these steps:

1.Activate the local loopback or remote loopback diagnostic.

2.Activate the test pattern. This may be done in one of two ways:

a.Enter e Selected Pattern from the System Diagnostics/Statistics menu and toggle the <Spacebar> until the desired test pattern appears.

b. Enter c Test Pattern and toggle the [Spacebar] to send the selected pattern.

c.One of two result codes will appear to the right of the Test Pattern listing:

OK Indicates that the received test pattern is error-free.

BE Indicates that there are errors in the test pattern (to deliberately insert errors in the pattern, toggle

Error Insertion to ON).

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