Harris Intraplex STL-160 Series Installation & Operation Manual page 39

2 – Functional Description
● The "2-15 Event" is declared if 2 or more errored seconds are detected in the most recent 15
minutes of operation and is cleared if there are fewer than 2 errored seconds in the most recent
15 minutes of operation. This Event is asserted for a minimum of 15 minutes.
● The "5-15 Event" is declared if 5 or more errored seconds are detected in the most recent 15
minutes of operation and is cleared if there are fewer than 5 errored seconds in the most recent
15 minutes of operation. This Event is asserted for a minimum of 15 minutes.
● The "86-24 Event" is declared if 86 or more errored seconds are detected in the most recent 24
hours of operation and is cleared if there are fewer than 86 errored seconds in the most recent 24
hours of operation. This Event is asserted for a minimum of 15 minutes.
In FTI mode, UAS is an alert if it does not interrupt service (that is, if the UAS condition is on the non-
active line) and is an alarm if it interrupts service (that is, if the UAS condition is on the active line). In
non-FTI modes, UAS is an alert or alarm condition under these same circumstances, but only if it is
selected as a line switching criterion.
In FTI mode and in UAS, the CM-5RB module
● Sends a T1 yellow alarm.
● Asserts an out-of-frame condition to all channel modules, which has the effect of muting audio on
most program audio and voice channel modules and asserting control signals on datacom to an
idle or off state).
● Changes the receive data sent to channel modules to all ones.
Like UAS, the Bit Error Rate (BER) is an alert/alarm only if it has been selected as a line-switching
criterion in FTI or non-FTI modes. If selected as line-switching criteria, BER and UAS result in an alarm
or alert even if redundancy is disabled; that is, LRDN CNFG = OFF or NOBK (line redundancy
configuration equals off or no backup).
2.1.4.12 T1 Transmitter Timing
In a terminal multiplexer, the CM-5RB common module enables selecting a primary timing source:
● Loop
● Internal
● External
In a drop and insert multiplexer, primary timing is always set to through. In the event of network or
link problems causing a loss of primary timing, an automatic, carefully controlled changeover to
fallback timing helps eliminate frame slips and maintain circuit availability. The fallback timing source
is factory-preset to internal.
The T1 transmitter timing can be set up differently on the primary and backup module. However,
during operation both the primary and the backup module operate from the same timing source,
which is the source specified for the currently active module. On the inactive or standby common
module, the T1 transmit timing is automatically switched to the same T1 transmit timing as the active
common. The indicator lights for timing are not affected. For example, if you switch the inactive CM to
loop timing, all indicator lights (Front Panel User Interface and ISiCL) are not affected and indicate
loop timing. However, the inactive CM the operates on the same timing as the active CM. Section
4.4.1 gives details on setting primary and fallback timing.
2.1.4.13 T1 Loopbacks
T1 Line Loopback can be used on either the active or backup line at any time. Equipment Loopback
can only be activated on the active module. If Equipment Loopback is active at the time the module is
switched inactive, it is automatically turned off and hidden from view on the front panel display
(Section 6.3.1 – T1 Loopback Use).
Harris Corporation
Intraplex Products
ACS-160 Series & STL-160 Series T1 Multiplexer Installation & Operation
Version 2.11, August 2011
2-17