Linux comes to the telephone

Linux desktops and servers are widespread. But Linux telephones? It could be the biggest use yet. Ben King talks to some early adopters to see how they like running their PBXes on an open source platform.

Open source in the enterprise is most widespread where end users don't see it - on specialised systems where the system only has to do one thing but has to do it well.

The best example is the Apache web hosting system, which has just under 70 per cent market share - but Linux is also widely deployed as an operating system for specialised security appliances.

There's one specialised device in an almost every office with more than a couple of staff - the private branch exchange or PBX, which handles incoming telephone calls, and distributes them to telephones on workers' desks.

These have typically been built on proprietary operating systems, from large companies such as Alcatel, Avaya, Nortel or Siemens. The arrival of IP-based PBX systems has allowed new entrants such as Cisco into the market. But a market already undergoing one revolution could well be fertile ground for another - the switch to open source.

The premise is certainly attractive. Instead of an expensive piece of proprietary hardware, you can get a generic server running a standard distribution of Linux such as Red Hat, and run a free open source PBX program, with no licence costs whatsoever.

The best-established open source telephony system is probably Asterisk, an open source initiative sponsored by Alabama-based company Digium. Another open source initiative, SIPfoundry, sponsored by Pingtel, was launched in Europe in May.

For Keith Dempster, IT manager at Southampton law firm Dempster Binning, the main reason for choosing Asterisk is that it's open source.

"We were moving buildings and we needed a new PBX," he says. "The ones that were available on the market at the time were heavily encumbered by what the market wanted to put with them."

"Asterisk seemed to offer a developing system, and one that was capable of doing whatever we wanted, and adding more flexibility."

They chose a system supplied by specialist VoIP company Telappliant, which installed the system and provides regular support.

He reckoned that the system cost around two-thirds of what he would have had to pay for a proprietary PBX, at around £4,000 for a 20-user system.

The major saving, he says, is in handset costs. He is able to use any SIP-compliant handset, and currently has systems from three manufacturers - Grandstream, Snom and Zultys - which all have different feature sets and prices. He paid just £50 for the Grandstream handsets.

It could also have brought a major saving if the firm had gone ahead with plans to open a second office. "We could have just installed another Asterisk box and linked the two together, and it would be like having one office," he says. "It would have been much more expensive to do that with a proprietary system."

The Asterisk project originated in the US and is still relatively uncommon in the UK. The only downside of Asterisk that Dempster has found thus far is that the automatic answering system still has a strong Alabama accent, and asks people to press something unknown in the UK, called a pound key (aka the hash key). He still hasn't found a UK version of the system.

Asterisk's major rival in the open source PBX market, SIPfoundry, is even less common in the UK but in the US it already has some keen advocates.

As Eliot Robinson, executive vice-president of Sterling National Bank, says: "We knew we were interested in running voice over IP, and we were interested in open source because, obviously, the price was right."

His company first looked at Asterisk but his engineers were plagued with a persistent echo on the line which they couldn't get rid of. They switched to a SIPfoundry-based system from Pingtel, which didn't suffer the same echo problem, and had an easier to use graphical user interface (GUI).

They now run a Pingtel-based phone system for 75 users in one of the company's offices. "The cost was very small," says Robinson. "Around $2,000 for a corporate licence, and we also asked them to do some custom work and training."

"One of the things that open source has done for us is given us lots of freedom. We use IBM and Dell servers. When we go to the PSTN we can use any subscriber service we want. We use Polycom phones - the price is right and the features are good."

Neither company was particularly concerned about the problem of support.

"We have the support from Pingtel and if you need to get support on Linux it is widely available," says Robinson.

Likewise, Dempster feels confident that Asterisk and Telappliant can meet all his needs. "Using Telappliant means that there's someone to shout at if things go wrong," he says. "But if you have a problem you can put a request out on the internet, and someone else will probably have solved that problem already."

Many organisations are still wary of open source, so moving to open source telephony will be too much of a jump for some.

People have higher expectations for the performance of telephones than they do for computers and reliability will be a big factor. Moving from a proven vendor to a solution provided by a group of unknown developers may be a step too far for many companies.

As Cisco's business development manager Ian Sherring says: "This is unproven technology for a business critical application. It may be simple for some companies that want to do it themselves but our approach, using proven software on proven hardware would tend to be more reliable."

However, the early adopters of open source telephony have certainly shaken things up. Last year Linux advocate John 'Maddog' Hall predicted that open source VoIP would be bigger than Linux, at least in revenue terms.

There's still some way to go before this comes true. But the arrival of such flexible, open and low-cost systems in a market dominated by high-margin proprietary products will certainly shake things up.