Tunnel Communications System

Voice Communication is a fundamental element of productivity and safety in a tunnelling project and MST offers two main solutions:

  • Leaky Feeder Radio for tunnels
  • Voice over Internet Protocol (VoIP) technology
  • FUSION Voice:  dedicated in-vehicle Wi-Fi push-to-talk

MST’s VDV Leaky Feeder technology is widely used, with radios from Motorola, Tait, and others,  but many tunnel projects are requiring more than just basic voice communications, wanting higher bandwidth to support video, TBM and road header data logging, etc.  Hence digital networks are being installed in tunnels allowing the use of our VoIP MinePhones for voice communications, and also provide the data capacity to support numerous other applications.

Benefits of VoIP

Emergency MessagingTunnel communications bases on VoIP enable users to make and receive person-to-person VoIP phone calls to communicate safety, production or technical information and instructions. This capability can be between personnel underground and between underground tunnel personnel and the surface, and if required to personnel anywhere around the world. The technology does not have the limitation experienced by two-way radio of a finite number of channels, and so facilitates any number of person-to-person calls at the same time.

However it still offers Push to Talk (PTT) functionality like standard radio system for group calls on up to 24 channels. Plus, unlike traditional radio systems, it does not require frequency licensing, as it uses the free 2.4 GHz WiFi band.   This is a very important aspect as it becomes increasingly difficult to secure frequency licenses in cities and urban areas where many tunnel projects are taking place.

Additionally, the MinePhone acts like a RFID tag, in that a MinePhones proximity to  underground access points allows  it’s location to be determined, and so enables personnel tracking in tunnels for the purpose of safety and productivity.


FUSION Voice is a unique platform, that brings together Wi-Fi based VoIP communications with traditional UHF or VHF radio systems onto a single, vehicle mounted device. Built on proven hardware (the Tait UnifyVehicle platform), FUSION Voice can operate on any 2.4 GHz Wi-Fi network, and is optimised for roaming on the MST IMPACT software network.

The unit offers something that has been missing from the market as more tunnels look to replace leaky feeder with Wi-Fi networks, with FUSION Voice being a VoIP equivalent of a traditional mobile radio.

FUSION Voice is easy to use, easy to install and power up, and has a 6m cable for mounting the control head, housing a loud 3W built-in speaker. The ruggedised form factor is fit for purpose in underground conditions. A Wi-Fi antenna is included and mounted on top of the vehicle to extend coverage. Built on proven hardware, FUSION Voice can operate on any 2.4 GHz Wi-Fi network, and is specifically optimised for roaming on the MST IMPACT software network, supporting central configuration.  The same unit can then be switched to operate on most UHF or VHF radio systems.

FUSION Voice adds to MST’s unified communications portfolio to allow the benefits of IP based communications to be readily available to the tunneling industry.

See below for more on Tunnel Communications using VoIP and Leaky Feeder Radio solutions, or contact us for more information.

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