Audio Monitoring - Listen In

This article describes how to monitor audio from selected substations using Simplex Conference in an ICX-AlphaCOm or AlphaCom XE system. The substation will be completely silent, but the microphone LED will go on. On IP substations and Turbines this LED can be deactivated.

There is one or more Staff stations and a number of Monitored substations. The Staff station(s) can select which substations they want to monitor by pressing a DAK key and then dialling the substation directory number, alternatively selecting a preconfigured DAK key. This application applies to both analogue stations, IP stations or a mix of these.

Operation

• Start monitoring: Dial 9535 + station number (these numbers can be configured on selected DAK keys).
• Stop monitoring: Dial 9535 + 9535 (or press dedicated DAK key twice).

If a new station is selected for monitoring, the currently monitored station will not be monitored anymore.

This application only allows for monitoring one station at any given time.

For monitoring multiple stations simultaneously, please see Multiconference.

Solution

All Staff stations are assigned their own simplex conference in the EXP field:

Setting UDP 1 and defining %exp

• Staff station 1 uses Simplex Conference 8201
• Staff station 2 uses Simplex Conference 8202
• Etc...

Each Staff station must also be defined as the default member of its "own" simplex conference:

Defining Simplex Conference default member

DAK1 on the Staff stations is programmed with the standard Two Step Event Trigger w/User Parameter, 9535 (feature 95/0). The programmed event reads the dialled directory number and commands the substation to enter a conference as speaker. To turn off the monitoring, press D1 twice.

Station programming:

• Staff stations are put in UDP group 1 - Staff
• Staff station 1 is assigned to SX 1 (8201)
• Staff stations are default members of their assigned simplex conference

Event Handler programming

An Event trigger start event is used to clean up the previous monitored station:

Cleaning up previous monitored station

Action commands:

$CONF L%udd(%1.phy) L8200
IND %1.phy %1.dak(I%udd(%1.phy)) 2 2 OFF

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The main event:

Monitoring main event

Action commands:

$DISCON_ST L%1.dir
Pause
Pause
IF %op(%2.dir,=,9535)
STOP
ENDIF
$CONF L%udd(%1.phy) L8200
WUDD %1.phy %2.dir
$CONF L%2.dir L%1.exp U2
$CONF_TALK L%2.dir U2 U1
IND %1.phy %1.dak(I%2.dir) 2 2 ON
$DTS L%1.dir 'Monitoring' U1
$DTS L%1.dir '%2.nam' U2
Pause
$DIP L%2.dir "ind stl 0 0"             {Turn microphone LED off for INCA stations}
$DIP L%2.dir "stinfo 5 'LedOff'"       {Turn microphone LED off for Turbine stations}

*The last three command lines in the action string are only applicable for IP stations.

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Additional

Simplex conferences survive a server restart, indications and conferance talk control do not. To prevent unintentional audio all Simplex conferences should be switched off at server restart using this event:

Removing SX off text

Action commands:

$CONF L84 L8200