TEMA TELECOMUNICAZIONI
IP PoE Multicast Encoder
AD615/SIP
MAS-AD615SIP-REV00EN
Page 11 of 28
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/SIP 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.
It is possible to program up to 16 audio receive addresses in the network terminals (AD6xx), each with its own
priority and its playback volume, so that the same terminal, if it is already playing audio (eg music) can be
interrupted by a higher priority stream (for example an announcement) and with a different volume (typically an
announcement must be played at a higher volume than background music). The audio supported by this mode is in
the G.711 format (aLaw or
μ
Law), G722 or linear high quality 16 bit (proprietary format, diffused through the AD615
device or an Intercom AA-540).
L’audio diffuso in streaming è utile per la generazione di messaggi vocali di annuncio, modalità detta anche
“Paging”. Ovviamente lo streaming è monodirezionale, nel senso che il flusso audio viene inviato dalla sorgente
alla destinazione ma non viceversa. L’audio in streaming può essere ricevuto da più terminali AD600
contemporaneamente (programmati con lo stesso indirizzo di Multicast in ricezione). With AD615/SIP
it is
possible to program up to 16 multicast transmission streaming addresses
(identifiable as distinct audio
channels). The first two are linked to the analog input and the position of the lever, while all 16 (including also the
first 2) can be addressed via a normal SIP VoIP call (the user chooses in post-selection which audio channel to
use).
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 or its SIP phone connected to the PBX 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/SIP 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/SIP 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/SIP 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/SIP
For multicast
announcers
AD611 n. 1 Multicast Address
239.255.12.42 (announcements)
LAN Switch
Fonia
AD611 n. 2 Multicast Address
239.255.12.42 (annuncements)
239.255.12.43 (music)
Fonia
AD611 n. 3 Multicast Address
239.255.12.43 (music)
Fonia
1
2
3
