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Total communications for intercom

Intercom is all about broadcast staff communicating with each other but now the race is on to make it part of a bigger technological communication network. Kevin Hilton looks at the options for allowing different equipment to talk together.

Technology is always moving on but the rate of change today is surprising even those involved in the innovations. A good example of this is intercom. As soon as a standard to connect different IP-based communications systems has been established, manufacturers are now contemplating linking up with other audio and video equipment through one of two networking protocols now under development.

Last year the European Broadcasting Union published Tech 3347, laying down guidelines and specifications for the use of IP in intercom systems. This is based on the SIP (Session Initiation Protocol) format, developed by the IETF (Internet Engineering Task Force) as an internet protocol for live communications to start and end voice or video calls.

With intercom operations moving more towards IP the main manufacturers in the field are producing Tech 3347 compliant systems. The next step is to expand the networking, integration and distribution capabilities of their products, with AVB (audio/video bridging or bridge) and OCA (Open Control Architecture) among the contenders.

AVB is a generic open standard based on IEEE (Institute of Electrical and Electronics Engineers) 802.1 and is designed for interconnection, networking and data centre bridging, carrying, routing and switching of audio and video signals over standardised Ethernet connections.

The standard is backed by the AVnu Alliance, with heavyweight support from members including Harman, Avid, Barco, Shure and Sennheiser.

The OCA Alliance was formed in June 2011 by nine professional audio companies: Bosch Communications Systems, d&b audiotechnik, Duran Audio, LOUD Technologies, Media Technology Systems, PreSonus, Salzbrenner Stagetec Mediagroup, TC Group and Yamaha Commercial Audio.

OCA is described as a system control and monitoring architecture and, because it does not have its own signal transport, is intended to work with any existing or future carrier. This includes AVB and the Audinate Dante IP over Ethernet networking system, which is also among the options for AVB.

The broadcast market is witnessing a proliferation of networking technologies right now, with Ravenna another prominent option. Created by Philipp Lawo, Ravenna is based on IP and has been developed by a subsidiary of Lawo, ALC Networx, working with a number of partners, including AEQ and Digigram. During NAB ALC Networx announced a partnership with the Telos Alliance, developer of the Livewire IP-over-Ethernet technology, to further expand Ravenna’s capabilities.

German intercom company Delec Audio and Videotechnik is an OCA Alliance member as part of Salzbrenner Stagetec Mediagroup. Delec founder Donald Dilocker sees AVB as “the technology for the near future”, as it is capable of audio over IP (AoIP); by updating Dante boards in its systems the company can offer AVB compatibility. But Dilocker views OCA as the more compelling technology. “Delec and the other Salzbrenner Stagetec Media Group companies are supporting OCA in order to ease the integration and compatibility of systems of any brand,” he says.

RTS-Telex is involved in the OCA Alliance as part of Bosch and has already incorporated the concept into its OMNEO media networking system. Senior sales manager Nico Lewis describes it as “absolutely the next step forward” and “the ideal professional media network” as it will allow the creation of a “single off-the-shelf network and cabling system for everything”.

While this is attractive to large manufacturing groups with a wide range of products, small manufacturers are less certain. Barry Spencer, general manager of broadcast at Trilogy Communications, says while OCA makes sense for companies like Bosch and the Stagetec group, which have ranges of different product types, from loudspeakers to intercom to mixing consoles, this is not the situation for everyone. “By doing all this some people might take their eye off their core business,” he comments.

Simon Browne, director of worldwide product management at Clear-Com, which is an observing partner with OCA, hopes some basic interoperability between systems will come about through the technology. “We all have open standards and so some common set of say, crosspoint control, could be found to help customers exploit their varied system solutions based on differing manufacturer’s equipment,” he says.

Other intercom manufacturers are leaning more towards AVB. “It is really pushing the envelope of what is possible in regards to integrated systems distributed over simple Ethernet infrastructures,” comments Riedel spokesman Nils Quak. “This will be a great leap forward in terms of installation design for the next years. AVB will be one of the biggest – if not the biggest – development in regards to realising intercom systems.”

Both the AVB and OCA camps are pushing on with formulating and establishing their respective formats. The AVnu alliance recently took on three new members, including beyerdyanmic, and appointed the University of New Hampshire InterOperability Laboratory (UNH-IOL) as the first test house for AVB certification. Work on pro-audio products is scheduled to begin during the first quarter of 2013. During the recent InfoComm show Alliance members including Bosch, Riedel, Sennheiser and Avid demonstrated the possibilities for interoperability using the technology.

On 7 June the OCA Alliance announced it had completed the OCA 1.0 specification, which defines the overall architecture of OCA and the communications protocols that can be used, as well as giving a detailed list of possible control and monitoring actions and functions.