INPUT NOT INDICATING BUSY

This is an ASIC internal test during a transmission, and indicates an ASIC failure.

TWO BYTE DATA CHECKS BAD

This test verifies multi-byte data transmissions for proper data. A failure could be caused by a -5-volt supply problem, a transmitter circuit failure, a receiver circuit failure, or an ASIC failure.

OVERFLOW COUNTER BAD

This tests the protection circuit-in the ASIC designed to prevent a host failure from over-filling the interface buffer and causing an error in opera- tion. This message indicates an ASIC failure.

BAD DATA, EXPECTING XX RECEIVED XX

A byte of data was sent, and the receiver circuitry interrupted the microprocessor. However, when the data was checked, it was not the same as when it was sent. This would indicate a problem with the twin-axial circuitry data paths.

PARITY ERROR DETECTED or PARITY FAILURE

This error indicates that the twin-axial receiver detected a parity error on receiving polls or data. This would indicate an error in the parity generation by the twin-axial output, malfunctioning of the parity checking circuit of the twin-axial receiver, or a poor cable connection.

INTERFACE DIAGNOSTIC LOOPBACK

Interface diagnostic loopback is essentially the same as interface diagnostics; the only difference is that no error messages are generated. A qualified technician can

use this test to check the circuitry with an oscilloscope.

Interface diagnostic

loopback is performed in basically the same way as interface

diagnostics; however, you must turn switch 8 off before starting. Always return

switch 8 to the on position when you are finished with interface diagnostic

loopback.

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