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2-18
VF dB Levels
The output level of any voice channel is selected as a channel parameter. The level may be spec-
ified in a range of +1.5 dB to -6.0 dB, with .5 dB between each level (a total of 16 selectable lev-
els). Output levels are selected separately for Node M and Node S channel outputs.
This level is an adjustment to an absolute output level selected on the CVSD Voice module, the
PCM Voice module, the ADPCM Voice module, the ASP Voice module, or the UVC/PCM and
UVC/ADPCM voice mod-ules. The output level is set to 0 dBm or +7 dBm by the position of
switch 51-2. Generally, that switch is set according to the requirements of the PBX or voice ter-
mination system to which the voice channel is connected (see the MEGAMUX PLUS installation
manual, Section 2, for more infor-mation on voice module switch settings). The setting of this
parameter adjusts the voice output above or below the level set by the switch; the purpose of this
adjustment is to compensate for cable attenuation or other system factors which offset the proper
output Levels of the voice channel.
You may change this level as part of the Diagnostics routines for voice channels. The Calibrate
routine sets the level to an optimal value, as determined by test circuitry on the voice channel
module. The Rcv dB routine allows you to make the same level selections that are made when
configuring a voice channel. When either routine is complete, the CRT asks whether changes to
the output levels should be changed. If changes are saved, the dB level entry for that channel con-
figuration is changed. This change occurs for the specified channel number in all stored configu-
rations where the channel is still configured for voice.
Alarm Cut-Off (ACO)
Every channel has the capability to generate alarms indicating failures related to that module's op-
eration. When alarms occur, they are reported by lit indicators on the front panel of the affected
module, and by alarm messages that are displayed in the system alarm scan, or an alarm scan for
that channel. When alarm cut-off is selected, the channel cannot report alarm conditions to the
system. ACO is useful when an alarm condition has been noted, but the channel continues to gen-
erate alarm messages; implementation of ACO prevents further messages from entering the
Alarm Scan displays and filling message buffers. This ensures that the alarm scan will report only
new alarms, and reflect only new problems which may occur in the network. When a channel is
set for alarm cut-off, the Alarm indicator on the channel module's front panel remains lit to indi-
cate the continuing presence of the condition.
ACO may be selected for all channels in a configuration. This action prevents the reporting of
channel alarms by the alarm scan; the alarm scan list will include only major alarms (those that
indicate a system-level problem). When ACO is set On for all channels, it cannot be turned Off'
again (except in version 3.20 and later) for all channels simultaneously; it may only be turned Off
on a channel by channel basis, or when a change is made to the configuration.
ACO's are now setup in diagnostics (all Universal MEGAMUX PLUS revisions).
036R660-000, Issue 10
NOTE
When changing voice output levels through the Rcv dB Levels
routine, it is preferable to save the selected levels in con figuration
memory. Otherwise, a discrepancy exists between stored channel
parameters, and actual channel operation. If a different
configuration is activated, and the levels set in the new
configuration are the same as the stored parameters for the pre-
viously active configuration, the voice levels set by the Rcv dB Levels
routine remain (the channel's voice output level does not change to
the levels set in. the newly activated configuration).
System Overview
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