Ears-104
Commercial in Confidence
Copyright © 2021, all rights reserved by Exacom, Inc.
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particular channel. There are currently three def ined trigger types, 1) VoxTrigger, 2) VoltageTrigger and
3) ContactTrigger.
Triggers are given unique names to identif y them elsewhere in the conf iguration f ile, but it is the Type
parameter that determines which of the three trigger types to employ.
VoxTriggers have the following settings available for configuration:
Type=”Vox”;
// Use signal energy as trigger
SampleCount = 256;
// Number of samples used to compute signal energy
StartDelay = 100;
// ms that signal energy must be over threshold to trigger
StopDelay = 2000;
// ms trigger will remain active af ter signal below threshold
Threshold = -30;
// Number of ThresholdUnit that activates trigger
ThresholdUnit = "db";
// or rms
The values specif ied in this section are the def ault values and will work in most cases. The most changed
value will be Threshold; StopDelay. SampleCount, StartDelay, and ThresholdUnit most likely will not be
altered in an installation scenario. Note: The def aults listed here f or StartDelay and StopDelay apply to all
Triggers, not just Vox.
Vox means voice-activated, or when activity is detected (based on signal power) it will begin recording
audio. Consider the f ollowing with the def ault parameters. Every 256 samples (SampleCount), signal
power level is updated. If this brings the levels greater than -30db (Threshold/ThresholdUnit), the trigger
f ires and begins the record operation,
but recording starts 100ms (StartDelay) in the past
. Recording
continues until the line-level drops below -30db f or a f ull 2000 ms (StopDelay), when the record
operation will be completed, and the recording f ile will be closed. Note: The purpose of StartDelay is to
prevent the beginning of a sentence f rom being truncated.
ContactTriggers have the following settings available for configuration:
Type =
“Contact";
// Use individual tip/ring voltages as trigger
Line = 3;
// ADC are out-of -band to data; we need to claim line
Active = "TLRH";
// TLRL, THRL, THRH - (T)ip:(R)ing:(L)ow:(H)igh
StartDelay = 100;
// ms
StopDelay = 100;
// ms
TipThreshold = 2500;
// mV
RingThreshold = -1000; // mV
Contact Triggers separately measure V+ (Pin 1) and V- (Pin 2) in ref erence to ground and if both pins
meet the conditions described b y the conf iguration f ile then a recording is triggered. The Ears unit
provides a +5VDC bias on V+ but does not on V-. This gives the needed f lexibility to wire to Contact
Closure circuits in scenarios where a voltage bias is or is not provided by the equip ment. For circuits
requiring that the Ears unit provides the +5VDC bias, attached Pin 1 (V+) and Pin 7 (Ground). For
circuits not requiring a voltage bias f rom the Ears unit, attached Pin 2 (V-) and Pin 7 (Ground).
In the case of using the above conf iguration data, the trigger is active when Tip (V+) is below the def ined
threshold and the Ring (V-) is above the def ined threshold. If the contact closure circuit is wired to V+ and
Ground, V- will always be idle at 0V. This means that if the Ring will always be above the def ined
threshold of -1000mV. For a recording to trigger, V+ must drop below 2500mV.
Note: The defaults for ContactTrigger are Active = “THRL” and both threshold voltages at 2500mV.
DifferentialTriggers have the following settings available for configuration:
