In order to make use of an AviaVox system it is important that connections can be made with existing systems at the Airport. A couple of interfaces need to be taken into consideration:
Interface Broker / AODB / FI(D)S interface
In most occasions only one of the above-mentioned sources will be used to retrieve actual flight information. Every time a change is made in the status of a flight, an ASCII-string (or XML-file) is sent from the AODB to the AviaVox System in a TCP/IP session over the local area network, mostly an Ethernet IEEE 802.3 (10/100 Mbps)
AviaVox requires specific data fields coming either from the Interface Broker, AODB or FIDS systems. These fields are necessary to drive the automatic speech system. AviaVox already has developed software templates for the making of these interfaces. In order to tune it exactly as needed, AviaVox will contact the manufacturers directly. With them, for instance, handshaking procedures and keep-alive sessions are being agreed upon.
AviaVox can already interface with a large number of AODB and FI(D)S suppliers amongst which ARINC, SITA, Ultra Electronics, RESA and others. In case the Airport uses a proprietary AODB or FI(D)S system, then AviaVox will develop the interface on the basis of the existing templates.
AviaVox delivers a converter that directly interfaces with the PA-System on the basis of “hard-contacts” or through a serial interface. This converter is known as the AVX-8. The AVX-8 is an audio and TCP/IP interface between the PA system and AviaVox system control unit. It runs a proprietary Windows version based on Windows XP Pro. Besides local network settings, the device does not store any configuration. All configuration needed to perform its task is sent by the Control Unit which is connected to the AVX-8 via the LAN. This means that it is easy to replace a malfunctioning AVX-8.
The AVX-8 has got three tasks:
o Controlling PA / broadcast system
This includes selecting zones to broadcast, detection of busy zones (to ensure the AVX-8 does not interrupt another external announcement), detection and processing when a running announcement is overridden by a user, etc. The AVX-8 has got serial interfaces for different PA systems (Bosch Praesideo, Honeywell GENT, AV Digital, Peavey TAPC, etc), but can also interface using hard contacts. Mostly, an additional interface, the AVX-8 Expander Rack (described in a separate data sheet), is used to achieve this. The interfaces which the AVX-8 supports can be extended by updating the software.
o Synthesizing speech and feeding into PA / broadcast system
The AVX-8 synthesizes speech which is fed into a PA system. The number of audio channels that can be processed simultaneously is limited by the hardware in the AVX-8 and the possibilities of the PA system the AVX-8 is connected to. By default, the AVX-8 is prepared with an 8-channel sound card.
o Galvanic isolation
This is the principle of isolating functional sections of electrical systems preventing the moving of charge-carrying particles from one section to another, i.e. there is no electric current flowing directly from one section to the next. It is an effective method of breaking ground loops by preventing unwanted current from travelling between two units sharing a ground conductor.
Within the AviaVox PA-interface, the audio outputs, as well as our command and signalling lines are galvanic isolated in order to avoid that unwanted ground loops occur. Exceptions can take place when the PA offers special commands- or signalling interfaces e.g. TTL.