Specifications

CSU/DSU MS DBU

NOTE

When this test is implemented, the far unit receives an OOS/OOF

message from the network and enters an alarm state.

Figure 12-7. DTE Only Test Diagram.

Test Purpose

The DTE Only test is used for the following purposes:

• Verify integrity of the DTE interface.

• Verify integrity of connection between DTE and CSU/DSU MS DBU.

Interpreting Test Results

A BERT tester must be used to interpret the test results of a DTE Only test.

12.3.4 DTE W

ITH

EST

ATTERN

The DTE with TP (test pattern) test exercises the internal data paths of the

CSU/DSU. The transmit data is looped back to the receive data at a point close to

the physical network interface. The test pattern is generated using the DSU/CSU’s

internal test-pattern generator. This test can be used to detect deficiencies within

the internal circuitry of the CSU/DSU MS DBU. Figure 12-8 illustrates the

loopback point and the data paths for this test.

Figure 12-8. DTE with Test Pattern.

LOCAL

DSU/CSU

DTE

NET Rx

NET Tx

DTE Rx

DTE Tx

Error

Inject

Test Pattern

Generator