June 2015 - Ed.2.1
Audio over IP decoders E411, E413, E415 & E417 technical manual
Page 6
2.3
Audio switching
Only one of the 10 possible channels can be played at a time. The device chooses which one must be played
analyzing their status (active/inactive), the assigned priorities and the user selection (only for the
“Background Music” layer channels).
The activation of each channel depends on the source type configured for it:
For the RTP audio streams, the channel becomes active when there is data present during more than 70
ms and becomes inactive when there is no data for more than 1 second.
When the audio comes from an SIP phone, the channel becomes active or inactive attending to the SIP
protocol. When the call is established, the channel is activated. When the call is ended, the channel is
deactivated.
SHOUTcast or ICEcast sources are activated when the connection with the configured server can be
established. If the connection fails, the source is deactivated.
Sources based on local files for the advertisement layer are activated by a time scheduling. When used
for the background music layer, they are always active, being played continuously in a loop mode if the
channel is selected.
Analog inputs used for the “Advertisements” or “Emergency” layers are activated by one of the digital
inputs in the device. When used for background music, they are always active. Each one of the analog
inputs can be assigned only to one input channel.
2.4
Digital I/Os
The E413, E415 and E417 models have two digital inputs and outputs.
Inputs:
In all decoders, can be used to control the volume of the background music channel being played.
When input 1 is active (contact closed), volume increases in 2 db each 500 milliseconds. Contact 2
decreases the volume in the same way.
In the E417, can be also used to activate the analog audio sources.
Outputs:
Can be used for activation of external devices (i.e. an amplifier, a light, etc.) when one (or more) of
the input channels are being played.
Further this, both inputs and outputs can be managed through the control protocol of the devices from
external applications, for instance to read sensors, activate doors, etc.
