Black Box Modem MD885A-R3 Uživatelský manuál stáhnout pdf (Strana 121)

120

Modem 34336

Figure 7-2. Analog Loopback Self-Test (ALBST).

The SELFTEST screen is displayed, with ON and OFF as the possible

selections. Select ON to activate the test. The EIA status screen is displayed

while the test is being conducted. If ER is present on the front panel, data

errors occurred. The ER indicator may flash on when the test is first started,

but it should quickly go out and remain off until the end of the test.

To end the test, press the ENT pushbutton to return to the SELFTEST screen.

Then select OFF.

7.7.3 A

NALOG

OOPBACK

ELF

EST

ITH

RRORS

(ST/E)

In the analog loopback self test with errors, data is sent and received by an

internal 511-bit pattern generator and receiver. No DTE or external BERT is

necessary. This test differs from the ALBST in that errors are injected into the

data flow every few seconds. The data flow is the same as that shown in Figure

7-2 (the ALBST).

External loopback

(leased line)

829 Block

Transmitter Receiver

Pattern

generator

Pattern

detector

1 2 ... 116 117 118 119 120 121 122 123 124 125 126 ... 149 150

Žádné komentáře

Black Box Modem MD885A-R3 Uživatelský manuál Strana 121