TEMA TELECOMUNICAZIONI
IP PoE Multicast Encoder
AD615/S
MAS-AD615-S-REV00EN
Page 11 of 23
6. OPERATING MODES
6.1.
Multicast Audio Streaming
In a LAN network, the Multicast term indicates the possibility to distribute an information like data, audio or video, to
a group of IP terminals of the Ethernet network. For Multicast are used class D IP addresses and they range from
224.x.x.x to 239.x.x.x. In our case AD615/S is able to transmit multicast audio starting from its analog inputs.
The audio can be generated from a PC software application (for example VLC) or directly from a CD or tape player.
Streaming audio broadcast is useful for generating voice announcements, also known as "Paging". Obviously the
Multicast audio streaming is unidirectional, the audio stream is sent from source to destination, but not vice-versa.
The audio streaming can be received from multiple AD600 terminals simultaneously (programmed with the same
multicast receive address). In AD615/S it is possible to program up to two Multicast streaming address (as separate
audio channels).
On receiving devices, the fact that it is possible to assign a priority level to each address (channel), give the
opportunity to create a background music service on the less priority channel and overlapping announcements
directly by an operator from its microphone base to another priority channel over the music channel.
Example
In a plant there are the systems showed in the diagram, connected to the same network switch.
AD615/S can make an announcement via Multicast to the address 239.255.12.42 or normally broadcast ambient
music at 239.255.12.43:
Many more devices than those shown in the example may be connected, there are no limits. The receivers are
programmed to receive only the announcement, the music plus the announcement or the only music that AD615/S
makes available on the LAN streaming.
System number 1 in the example figure will only play the announcement message, the system number 2 will
broadcast the music that will be interrupted due to the broadcast of a priority announcement, the system number 3
will always and only broadcast the music without ever listening to messages (the music will be interrupted anyway
for the duration of the message being sent to other devices).
To get a continuous service of ambient music you will need to have a second AD615/S in order to dedicate a
system for the transmission of music and the other to the transmission of the announcement messages, because
with just one system the music channel will be interrupted when a microphone announcement is being
broadcasted.
AD615/S
for Multicast
announcements
service
AD611 n. 1 Multicast address
239.255.12.42 (announcements)
LAN Switch
Audio
AD611 n. 2 Multicast address
239.255.12.42 (announcements)
239.255.12.43 (music)
Audio
AD611 n. 3 Multicast address
239.255.12.43 (music)
Audio
1
2
3
