Filter
Top Products
19
5.3 TEST MODES
The Model 1088 offers two proprietary loopback test modes, plus a built-
in V.52 BER test pattern generator to evaluate the condition of the
modems and the communication link. These tests can be activated phys-
ically from the front panel.
Overview
Figure 11 below shows the major elements used in the loop-back and
pattern tests available in the Model 1088. Each block has several func-
tions. Following Figure 11 are descriptions that show how the elements
are used during Test Modes.
Figure 11.
Block Diagram Model 1088
Framer
The framer is used to determine the status of the line. In normal
operation the framer transmits and expects to receive framed
packets from the far end. If the framer receives framed packets
from the far end, the DSL Link LED will be active. If framed pack-
ets are not received, the DSL Link LED will be inactive. The restart
procedure uses this information to determine if a valid connection
ER
(Flashing Red) - blinks ON/OFF after a 511/511E
test has timed out. See Section 5.3.3 (Test Pattern
Generator) for more information.
• Flashes once to indicate that a CRC error has
occurred (during normal operation) or bit errors
have occurred (during 511/511E tests).
• Only at power up, blinks once every 200 ms if the
DTE Rate is set to an unsupported settings
TM
(Active Yellow) glows yellow to indicate that the
Model 1088/K has been placed in Test Mode. The
unit can be placed in test mode by the local user or
by the remote user. The TM LED will flash for
400 msec when a valid packet is received from the
Model 1001MC.
Pattern
Gen/Det
Loop
Contr
ol
Loop
Contro
l
Pattern
Gen/Det
Processor
Processor
Framer
Framer
Line