Specifications

December 2008 Page 7–9
Chapter 7. Maintenance Module
7
•Yellow alarm is transmitted from the side
detecting the out-of-sync condition. When
CGA is enabled, the Yellow alarm is trans-
mitted during Red alarm period. In this
case the side receiving the Yellow alarm
will receive it for a minimum of 12.5 sec.;
during this time the trunk conditioning is
performed on the voice modules. If CGA is
not enabled, Yellow alarm duration follows
the out-of-sync timing from the remote side
with no delays or extended timing and
trunk conditioning is not performed.
•Trunk conditioning is the action of writing
fixed signalling bit patterns to the voice
modules when a stream is in Red or Yellow
alarm. Trunk conditioning occurs only on
the following channel modules, V4W
(configured with Signaling enabled), V2T,
V2W, FXO & FXS. The voice module
must be mapped to a stream which has
CGA enabled.
7.4.4 Rapid Squelch - MV5, T1/E1
In order to prevent channel modules from
receiving noise during sync loss, channels are
squelched whenever out-of-sync errors are
present. A squelched channel means that the
channel is programmed to receive an all ones data
pattern. With normal squelch functionality,
channels are squelched after 3 sec. of sustained
out-of-sync errors.
FOCUS chassis which support rapid squelch (see
note) have the ability to squelch the channels upon
the first out-of-sync error thus shutting down the
channel in less than 5ms. You must individually
select channels, or pass-through circuits, on which
rapid squelch should be enabled. This is done on
the channel map page of the FCS. You click on the
desired drop or pass-through connection and
select “Enable Rapid Squelch” from the pop-up
menu.
Squelch is removed and channels are restored
after 500ms have elapsed with no sync errors.
By selecting rapid squelch, any sync loss detected,
even if only one frame, will block the channel for
a minimum of 500ms. Without setting rapid
squelch, temporary sync losses of up to 3 seconds
will not be squelched and it will be the responsi-
bility of the connected equipment to ignore the
errored data seen during sync loss.
The channel map retrieved from FOCUS will
indicate channels that are currently squelched
(Yellow time slot) in addition to channels that
have rapid squelch enabled on them (Sky Blue
time slot). (See note). As with all channel module
assignments, rapid squelch assignments are sent to
FOCUS when you click the send map button.
To determine if rapid squelch has occurred, look
for the following system event:
“Rapid squelch for stream X1-1” (or X1-2
etc.) and “Rapid squelch for stream X1-1
CLEARED (or X1-2 etc.).
Off-line, rapid squelch is only available when the
framer type is set to TE1/T1 or TE1/E1. If you are
creating configuration files, set the framers this
way in order to create configurations with the
rapid squelch enabled. You may also
enable/disable rapid squelch per channel module
by clicking directly above the module’s identifier
label.
7.5 Drawings
The schematics for the main board/CPU board are
available by request.
NOTE
Rapid squelch is only available with the MV5
and T1/E1 firmware of F/Exx5.09.00 and FCS
version 3.12 & later.
NOTE
Trunk conditioning options are only available
with the T1 MV5 and the V4W module (both A
& B channels). V2W, V2T, FXS & FXO modules
have fixed trunk conditioning (channel forced
idle for 2.5 sec. when busy) only.