MT56DSU2 Owner’s Manual
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4.2.6 96 Indicator
The 96 LED lights when the “Data Rate” selection is set at 9600 bps. This indicator will be off for
all other data rates. Refer to Chapter 2 for switch settings.
4.2.7 48 Indicator
The 48 LED lights when the “Data Rate” selection is set at 4800 bps. This indicator will be off for
all other data rates. Refer to Chapter 2 for switch settings.
4.2.8 CTS Indicator
The CTS (Clear to Send) LED lights when the MultiDSU56K generates a CTS in response to
either an RTS signal received at the DTE connector, or RTS forced on by the corresponding DIP
switch. If the Circuit Assurance option is enabled, the CTS will be off whenever Carrier Detect is
off.
4.2.9 RTS Indicator
The RTS LED lights when the RTS signal is received from the DTE. The DIP switch for RTS
Forced On does not affect this indicator. Refer to Chapter 2 for switch settings.
4.2.10 NS Indicator
The NS (No Signal) LED lights when no signal at all is received from the network, or when the
signal is too weak for normal MultiDSU56K operation. This indicator will also flash to indicate that
errors have been detected when using the Test Pattern diagnostic feature.
4.2.11 OOS Indicator
The OOS (Outage) LED lights when an outage condition exists. This occurs when there is a
failure in the digital service detected by the network, and the telco sends a repetitive OOS
sequence.
If this indicator is on, check the remote DSU for proper installation and operation. If the remote
DSU is installed and operating correctly, then report the Out-Of-Service condition to the
telephone company.
4.2.12 TM Indicator
The TM (Test Mode) LED lights when one of the Test switches is set to the down (Test enabled)
position. When the TM LED is lit, normal operation (network transmit/receive) cannot occur. Refer
to the “Diagnostic” Tests section for more information.
4.3 Diagnostic Tests
The MultiDSU56K is set to a default of Normal (non-diagnostic) mode at the factory. When
diagnostics are to be run, change the DIP switches as described in Chapter 2 of this manual.
When a failure occurs in the digital facility (telco equipment), the network will detect the failure
and send a repetitive OOS signal sequence to your equipment. Your equipment can detect local
loop failure by the absence or distortion of the digital signal. If an OOS is received when data is
expected, check the remote (far-end) transmitting equipment. If the remote equipment is
transmitting properly, contact your telephone company. If the telco is required to perform remote
tests, the channel will be temporarily interrupted and loss of data may occur.
The following sections describe the tests that are available for the MultiDSU56K.
