Paradyne 3510 - Manual (Page 40)

COMSPHERE 3500 Series Data Service Units
3-18 March 1999 3510-A2-GN32-60
2600 Series DSU Emulation
Several tests are available to an network management
system (NMS) user to investigate trouble conditions on a
circuit with 2600 DSUs.
Disruptive Test and Control Commands
As a result of abnormal status condition or a trouble
report from another source about a 2600 circuit, the NMS
operator can perform one or more of the following
disruptive tests:
•
Abort Test: This command aborts or stops any
ongoing test or test configuration in which a
2600 DSU is involved. It is effective for conditions
initiated by the NMS.
•
Digital Test: A timed Digital Test of specified
length can be performed on a multipoint circuit
between the control DSU and a designated tributary
DSU. At the start of this test, all tributary DSUs are
placed in Test mode, and then the designated
tributary DSU is placed into Digital Loopback. The
control DSU then sends the test pattern and
compares the returned signal for errors. If no errors
are found, the test passes. This means a signal was
successfully sent from the control DSU through the
DDS network, to the designated tributary DSU, and
back again. Thus, a problem on the circuit is
probably in the remote terminal equipment.
On multipoint networks, the tributary DSUs that are
not involved in the Digital Test are placed in Test
mode for the duration of the test. During Test mode,
the DSU’s transmitter is disabled to prevent
potential interference with the Digital test.
The tributary DSU front panel indicators are in the
following configurations during a Digital Test:
Specified Tributary DSU – Remote Loopback
REM indicator slow flash
TEST indicator ON
DL indicator ON
Other Tributary DSUs – Test Mode
REM indicator slow flash
TEST indicator ON
•
DSU Disable/Enable: A 3510 DSU can be disabled
from an NMS. When the DSU is disabled, it
ignores signals on its send data and request-to-send
leads and clamps its received data signal to MARK.
This is the same condition as in the Test mode. The
difference between a DSU being disabled and
placed in Test mode is the method of restoring the
DSU to a normal mode. The DSUs in Test mode are
restored when the test is concluded or aborted;
DSUs in Disable mode are only restored when an
enable command is received. Disabling DSUs is
useful when the terminal equipment is not ready for
service or when multiple terminals have been
assigned the same polling address.
Disabled Tributary
FAIL/STR/DSBL indicator ON
REM indicator slow flash
•
Loopback Commands: A 3510 DSU can be placed
in a Remote Digital Loopback from the NMS. This
permits the DSUs to be tested with external test
equipment, to be tested by special test messages
sent and checked by a host computer.
Tributary In Loopback
REM indicator slow flash DL indicator
ONTEST indicator ON
•
Transmit Test Pattern: This command is used to
cause a 3510 tributary DSU to transmit its test
pattern. If the other end is also placed in Test
pattern, it is possible to conduct an End-to-End Test
and isolate marginal troubles to the send or receive
direction.
Tributary in Test Pattern
REM indicator slow flash
TP indicator ON
TEST indicator ON