ASL Safety & Security offers IP-based long-line public address and voice alarm (PA/VA) systems for rail, light rail and other mass transit infrastructure hubs. ASL pioneered the use of energy-efficient Adaptive Class D amplification in its PA/VA range, removing the need for forced cooling. The company’s fanless wall and rack-mounted systems have received extensive endorsement on global infrastructure projects.
Monitored public address system
ASL’s iPAM product is a monitored public address (PA) solution that has been created specifically for rail projects. ASL integrates routing, amplification, PC/DVA and CIS software functions into a robust voice over internet protocol (VoIP) offering. Where necessary, a graphical user interface (GUI) can be provided by ASL’s mini-iVENCS software, which can operate from Linux, Windows, Solaris and OS X. Clients benefit from dual redundancy should they require it.
As well as offering core public address – predominantly platform and public concourse announcements – iPAM provides general customer information system (CIS) functionality such as digital voice announcements (DVA) and text to speech. iPAM also supplies network-wide fault reporting to a client’s control centre workstations.
Operators and maintainers receive status information on the PA system and potentially on related disciplines such as CCTV and access control. BS5839:8-compliant voice alarm can be provided using ASL’s VAR router and V400 amplifiers. Client feedback on a UK light rail network has stressed the benefits of flexibility and scalability within this architecture, particularly in environments requiring multiple controls.
Dynamic ambient noise sensing platform announcement audibility system
ASL are revolutionising audibility of platform announcements with their dynamic ambient noise sensing (DANS) system. Conventional noise sensing equipment at railway platforms and infrastructure hubs takes a crude sample of background activity before the broadcast and cannot adjust for varying ambient noise. But ASL uses digital signal processing (DSP) to distinguish background noise from the announcement, continuously optimising volume levels.
This ability to address the problem of garbled announcements and also contribute to noise abatement confirms ASL’s leadership position in the PA/VA sector.
Voice alarm and public address microphones
In order to optimise the performance of its PA/VA products, ASL manufactures a full range of voice alarm and public address microphones including office-style desk consoles and rugged products for demanding sectors of the transport industry. Microphones on the company’s ambient noise sensors have recently been redesigned to operate in temperatures as low as -50°C on the Norwegian rail network.
Models with customised graphic displays are available as well as units that can be adapted for application-specific usage. A touch-screen microphone is available for projects where fully-customised zone selection displays are required. This microphone is based on ASL’s PC/DVA system and can be connected directly for conventional PA use in the manner of a standard unit. It can also use a VoIP approach to broadcast across an IP-addressable system.