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Network Audio


The NetSpire Fixed Infrastructure communications system is a TCP/IP based unified communication platform designed for public address, automated announcements and emergency audio systems for fixed infrastructure projects such as train stations, road tunnels, airports, mines and other industrial environments.
The system is suitable for control by both central operators, and local operations staff.

The solution covers the following types of communications required for fixed infrastructure projects:

  • Public Address (PA)
Digital public address with network enabled operator call stations and amplifiers.
  • Digital Voice Announcement (DVA)
Playback of digitally recorded announcements is integrated into most NetSpire devices.
  • Automated Announcements
announcements can be automated, for example to provide passenger information. Interfaces to signalling, and SCADA systems are supported.
  • Visual Communications
Control of LED and Flat Panel displays for visual message that are synchronised with audio content.
  • Third-party Integration
The NetSpire SDK provides third-party control and monitoring of the entire system, perfect for integration into SCADA systems and providing integrated HMI solution.
  • EN60849 Compliant
The NetSpire solution can form part of an EN60849 compliant system for emergency audio.










NAM2i and NAM8i


IP Public Address Call Station

Network Audio Router

Network Audio Contoller

Network Amplifier Module

Communications Exchange Server

Multi Zone Network Paging Station with Touch Screen interface

4 Channel Analogue Audio Network Gateway

Network Amplifier supporting upto 8 Channels. Combinations of 100V Audio and Hearing Loop channels

IP rated, Outdoor, field Mounted Amplifiers with 2 and 8 Channel Amplifiers

Central Server for system control, configuration, prioritisation and management


NetSpire™ uses open, standards compliant protocols to transmit digital audio signals on a standard data network.
The result is audio quality which is superior to a traditional public address system, no matter the distance the operator from the target zone or how many zones are addressed.
The use of a standard data network simplifies system design, and leveraged the rapid cost reduction in IT industry infrastructure.

Example System Diagram:


networkaudio - system diagram  


EN60849 Emergency Certified

NetSpire™ is compliant with EN60849 sound systems for emergency purposes. The system integrates with fire panels, Warden Intercom Phones (WIP), audio health and fire alarm signals.

The NetSpire™ system constantly monitors devices in the system. Health monitoring is performed from the microphone all the way to the loud speakers.

The failure of an individual speaker or microphone can be detected and escalated as a fault alarm in the system.

Auto-configuration and Plug and Play

After initial system configuration, a permanent record of the device configuration is automatically maintained . In the even ar device is swapped-out, the configuration is automatically restored without user interface. This provides true plug-and-play support and reduces training requirements for technicians. It also eliminates the potential for replaced equipment to be incorrectly configured.

Web-based Management

NetSpire devices are designed for ease of installation and maintenance. The initial installation, configuration and deployment can be performed using a standard web-browser by a single technician on the train. The configuration web screens allow authorised technicians to configure and view device settings while making real-time changes to the operational parameters.

Examples of the web interfaces are provided below.

Standard Open Protocols

All core protocols used in the system are international standards such as SIP, RTP, NTP and SDP. Devices such as standard SIP end points can be readily incorporated in the system. Where extension protocols are utilised, they are fully specified and documented.


 webconfig-eq  webconfig-dynamics  webconfig-gain  webconfig-status  webconfig-diag

Parametric EQ and General Filters

Audio Dynamics Control

Gain Management

Device Status


Configure filters per device or zone

Specify compression curves and limiter functions

Calibrate and configure absolute and relative gains

Real time status of individual device Initiate real-time diagnostic functions and test tones.


One Cable Networked Solution

All Audio, media and control and status information is sent using an industry standard Ethernet interface. The platform is compatible with all common network topologies and routing arrangements and does not rely on broadcast packets.

802.3af compliant Power over Ethernet is utilised in many NetSpire devices such as operator call stations and intercoms. This further simplifies cabling, installation time and testing requirements.

Distributed Digital Voice Announcement

Each NetSpire devices incorporates independent recorded digital voice announcement capabilities. This means components such as amplifiers can independently make announcements without relying on shared or remote components. This facility provides added flexibility, for example it is possible to make a “door obstruction announcement” to a specific location.

Low Component Count

A complete passenger emergency, PA, Passenger Information and Crew Communication system with train radio integration and disabled user support can be implemented with 4 NetSpire components. This simplifies design, reduces space requirement and eases management of spares.

High Fidelity, Digital Audio System

All audio in the NetSpire system is sent as digital data. This provided increased audio bandwidth over traditional systems and removes issues associated with noise in analog environments.

Disability Compliance

The NetSpire system supports compliance with international disabled access requirements such as EN60118-4 for hearing impaired users. The NetSpire TGUI is one of the only products in the world to support efficient Class-D transconductance amplifiers for driving Induction Loops.

Redundancy and Fault Tolerant

The NetSpire CXS servers provide automatic redundant failover between the active and hot-standby servers. This ensures there is no single point of failure and system operation can continue in the event of a CXS unit failure, or network partition.

The NetSpire NAC and NAM amplifier units can also be configured in one of several redundant configurations. These include hot-bussing, where each alternate speaker is driven by a different amplifier channel (or different NAC unit), and redundant failover where two NAC units share responsibility for driving the same speaker bus.

Interfacing with Third-party Systems

The NetSpire™ SDK for Java, .NET, C# and C++ allows custom software solutions to control and monitor the communications system.

SDK Languages

NetSpire™ devices support programmable isolated digital inputs and outputs for interfacing with devices such as buttons, door indicators, TMS signals, etc. A web integrated schematic logic tool is provided to allow code free implementation of custom functions.


In addition to the NetSpire SDK and Logic Editor, NetSpire devices have the following interfaces and options available for integration:

  • RS232 / 485 interfaces
  • SCADA Device Drivers
  • SNMP monitoring and control interface

 scada - smart example

Sophisticated Self Health Checking

NetSpire devices continually self-monitor operation to ensure they are functioning correctly. Faults are identified proactively and reported without the need for manual inspection in most cases.

Fault detection options extend to supporting acoustic loop back checking and speaker bus impedance checking for identifying problems with intercoms or external cabling and speaker faults.

Scalable and Extensible

The distributed design of the system enables it to be scaled to support thousands of audio channels and attached devices.

All system components are software upgradeable over the network, allowing additional functionality to be added to the system without removing or physically visiting each device

High Level of Integration

The integration of the audio, display, passenger information, train radio integration and system monitoring into a single system reduces risk, cost and complications associated with integration components from multiple manufacturers.

An example of this high level of integration is the NAC Network Amplifier. This single 2RU device incorporates:

  • Digital Signal Processing

  • Digital Inputs / Outputs

  • Digital voice Announcement

  • Up to 8 Induction Loop outputs

  • Up to 8 Speaker bus outputs

  • Fault Tolerant Power Supplies

  • Compressor / Limiter

  • Network Audio Streaming Interface

  • Speaker Bus Monitoring

  • Ambient Noise Compensation

  • Matrix Mixer

In a traditional environment, this would typically require up-to 6 discrete devices.



Click here to view our Network Audio Components