Configuring the Microphone Audio Parameters. ASL INTERCOM SMC02G

SMC02G/SMC02F/Variants - Product Manual

5.7 Configuring Microphone Audio Parameters

5.7.1 Microphone Input Gain

VAR4/12/20 Menu: Configuration Æ System Æ Router Æ Inputs Æ Mic/Line Æ < I/P # nn – MIC/LINE nn >

Æ < Zoned Fire Microphone or Paging Microphone > Æ Audio Æ Gain Æ PreAmp

ACU/VAR8-ACU Menu: Configuration Æ System Æ Router Æ Inputs Æ Mic/Line Æ < I/P # nn – MIC/LINE nn >

Æ < Zoned Fire Microphone or Paging Microphone > Æ Audio Æ Gain Æ Input

Possible values: –63dB to 0dB (1dB steps)

System default configuration: –14 dB on VAR4/VAR12/VAR20

–20 dB on ACU and VAR8-ACU

The input gain of each audio input should normally be set so that all inputs are balanced, and give the same output level on each of the outputs.

Initially ensure that the microphone input gain is set to its default value. Any further volume adjustments should be made using the output specific relative gains.

On VAR4/VAR12/VAR20, ensure that the line sensitivity ( Sens.) is set to its default option, which is ‘Line’.

This adjustment works in real time, so it can be experienced immediately on any live routes.

5.7.2 Microphone Surveillance Tone Detection

Menu: Configuration Æ System Æ Router Æ Inputs Æ Mic/Line Æ < I/P # nn – MIC/LINE nn >

Æ < Zoned Fire Microphone or Paging Microphone > Æ Audio Æ Surv

Possible values: –40dB to 0dB (1dB steps)

System default configuration: ‘–40dB’

If this surveillance is enabled, then in the absence of a surveillance tone, an Input Audio fault will be raised and logged. This would indicate that the microphone audio connection is broken, or is a poor connection.

The detection threshold level is adjustable as follows. a. Configure and Level (dB)= – 40 , enabling the Router to detect the presence of the low frequency surveillance tone, that is generated by ASL microphones. b. Clear any existing faults by pressing the FAULT CLEAR button on the system front panel. c. Make sure that no fault is reported for the SMC02. Any fault reported by the SMC02 at this stage should be cleared, see Section “ 6 Fault Finding ” (page 48 ). d. Raise the surveillance tone level slowly (1 dB step) from –40 dB until the “IPXX AUDIO INPUT” fault is reported. Where XX is the Mic/Line input to which the SMC02 is connected. e. Set the surveillance tone level to 4 dB below the level that caused the fault to be reported.

E.g. if a –18 dB level causes the fault, then set the surveillance tone level to –22 dB. f. Make sure that no fault is reported for the SMC02.

Issue: 02 complete, approved

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