Document: LT0732 QE20 Fibre Networking User Manual
Issue 1.0 24 May 2023 Page 2-9
2. Operation of Fibre Network
Data Communication
When a QE20 panel sends data it may be sent as a packet to the specific QE20 (SID
number) that needs to receive it, or as a broadcast to all QE20s. With fibre
networking each message is sent by the RS485 Network Module to the PIB, which
looks up a table to identify the IP address of the destination QE20 SID and then
sends the message to the PIB at that IP address using UDP. The receiving PIB
passes the message on to the QE20 Network Module, which forwards it to the
Controller to process. For broadcast messages, the PIB will send the message to
each PIB that it knows about (unless filtering is programmed).
The PIB can have a pre-programmed table of SID numbers and IP addresses, or it
can automatically build this table from messages it receives from the QE20 panels
and PIBs on the network.
The Moxa fibre switch takes care of sending the UDP and VoIP packets around the
fibre ring, especially when the ring is broken.
Audio Streaming – PIB VoIP Proxy
When Speech and WIP ALL-CALL is sent on the network, it quite often needs to be
sent to many places at once. For example, a Speech announcement to the whole
network would require the speech audio to be sent to every other node. This
presents quite a burden on the sending device, and as the ATAs do not support
streaming of audio to more than 4 devices, something else needs to do this.
The PIB can be configured to stream audio to up to 31 other nodes. This function is
called PIB VoIP Proxy in the PIB. Each PIB can have up to four streaming channels
configured. When it receives a streaming request on a channel it will attempt to
make a VoIP call to a pre-programmed IP address to get the source VoIP data
stream (usually the ATA in the same panel). Any data the PIB receives is then
streamed to all the remote devices that have connected to the channel. This way
each PIB can fan out the streaming audio to 31 other nodes. By having multiple PIBs
connect to the original source ATA, or daisy-chain from one to another, the single
audio source can be fanned out to a virtually infinite number of destinations.
Speech Audio Communication
The following is a simplified description of how Speech audio is distributed in a QE20
fibre network. In the event that something is not working, it may be useful to track
the actual operation against the description below.
2.1.1 Speech
When a Speech announcement is initiated from a QE20 that involves distribution of
the speech to other QE20 panels on the fibre network the following happens in
sequence: –
1. The user at the QE20 selects one or more zones for Speech. This panel is
hereafter referred to as panel A.
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