They've been hard at work, deep in the bowels of most large organisations for many years, but now their future is looking bleak. The PABX has been a vital component of corporate telecommunications infrastructures for years. Tirelessly routing incoming and outgoing phone calls, the devices underpinned most activity in the modern office.
Now, the rise of technologies such as internet protocol (IP) networks and SIP (session initiation protocol) is causing growing numbers of IT managers to weigh up whether they need a PABX at all.
The two factors that have so far saved many PABXs from a one-way trip to the scrap heap are cost and complexity. The devices have traditionally been very expensive to purchase and so have been amortised over a long period of time. They have also usually come with long-term support contracts.
The complexity stems from the proprietary nature of PABXs, together with the necessary wiring and handsets spread throughout companies. If organisations perceive that a move to IP will require major upgrades in these areas, the pace of adoption is naturally slower.
But despite these factors, even PABX vendors can see the writing on the wall. The advantages and flexibility offered by IP-based systems make them simply too compelling to ignore.
Nortel Asia Pacific's chief convergence architect Mick Regan says the PABX has evolved relatively slowly for the past 20 years, but the pace is now changing dramatically.
"I believe that by about 2007, 50% of organisations will have moved into a converged (data and voice) environment and be using IP-based systems," he says.
"Instead of a standalone PABX, increasing amounts of company voice traffic will be handled by IP systems. The PABX will be just another server connected to the network."
Siemens general manager, partners and resellers, David Healy says the maturation of voice over IP (VoIP) has led to rising numbers of companies examining and experimenting with the technology. But he cautions that technology is only part of the equation.
"There are discussions taking place around whether IP-enabled PABXs or pure IP systems are the way to go and each vendor has its own take on this," he says.
"But from my perspective, it is not just about pure technology. Everyone agrees that IP is definitely the way to go, but real business value does not come from just putting in some IP pipes and phones."
Healy says the real value will be gleaned from 'second generation' IP, where applications are tightly integrated with a company's voice infrastructure. "There is still a long way to go with first generation. We've certainly crossed the chasm but there are a lot of companies that are yet to take the first step," he says.
The Siemens vision involves the fusion of corporate data and voice infrastructures with mobile networks to create 'seamless communications'. The company points to its OpenScape product as an example of how SIP can be used to achieve this goal.
Healy says extracting value from IP systems can be as simple as an organisation having an easy method of locating its people. This can be achieved without ditching the PABX but by augmenting it with other technologies.
However, others in the industry warn that sticking with a PABX, albeit an IP-enabled one, could cause troubles further down the line.
In a recent report, analyst firm Gartner describes IP-PABXs as an "architectural dead end". Because they are built on proprietary rather than open standards, they are unable to take advantage of many of the changes being made in telecoms technology.
The report says future voice technology will be an application rather than an infrastructure and this point cannot be reached with traditional PABXs. Gartner believes wider usage of SIP technology will radically change the way communications systems are built, because it allows applications to be independent of the underlying equipment and systems.
Avaya solutions development manager Robbie Kruger says moving to such an open infrastructure allows companies to use existing software applications in different ways.
"Customers are asking for a more open, scalable and flexible environment," he says. "They want to integrate applications such as databases, Microsoft Outlook and Lotus Notes with their voice services.
"If I try to ring someone and they are not available for a voice call, they may still be available via instant messaging (speech to text) or via email. The system will know this and allow me to communicate in that way. I might be able to tell their availability by simply clicking on their name in Outlook."
Avaya is trumpeting its strategy that harnesses so-called business communication applications. By tying core applications to voice using tech-nologies such as SIP, process improvements and higher productivity should be the result.
"I can certainly see the day when there will be no PABXs in companies," says Kruger. "You can move completely away from legacy hardware to a server-based environment."
Another question facing organisations wanting to move away from the PABX and adopt an IP-based infrastructure is whether to install the required equipment on their premises or opt for a hosted service from a telecommunications carrier.
The latter option, often known as IP centrix, was trumpeted as the next 'big thing' by vendors and analysts alike just a few years ago. The concept allows companies to have no voice switching equipment on their premises, with all calls going via the carrier's exchange.
Carriers talked up the idea as a way of reducing complexity and costs. But despite the excitement, reality has been somewhat different, with organisations proving somewhat reluctant to adopt the service.
Ericsson Asia Pacific solutions design manager Zac Westbrook says there had been early predictions that, by 2008, as many as 25% of firms would opt for a hosted centrix approach when migrating to IP. These predictions have now been downgraded to around 10%.
"Sometimes companies found an out-sourced solution just didn't fit with their operations," he says. "There are also concerns over security."
Nortel's Regan says early centrix offerings were seen as an 'all or nothing' approach which many organisations didn't really feel comfortable with.
"Now things have matured and you can have a combination of hosted and in-house systems as required," he says. "For example, databases can be kept internally while the SIP servers are hosted by the carrier. This makes the whole thing more attractive."
Healy says most companies he talks with are keen to be "in control of their own dest-iny" and so opt for in-house systems. "Because vendors, on the whole, are working with open standards, companies can link together different systems to achieve what they need in house," he says.
Looking further down the IP telephony path, and once companies unshackle themselves from their PABXs, some vendors predict fixed-to-mobile convergence will move into mainstream use.
Rather than employees having a desk phone and mobile handset, this stage blends the two devices into one - a particularly attractive thought for organisations with a mobile workforce.
Such a system can work in a number of ways. Handsets can be configured to connect via a wireless network when an employee is within the office, and roam to a mobile network when outside.
Alternatively, arrangements can be made with a preferred carrier to have all calls - internal and external - routed over their mobile network, in a centrix-style architecture.
Ericsson's Westbrook says his company has installed such a system for computer company HP in Sweden. HP employees are given a single mobile handset that replaces their traditional desk phone. All calls are carried over a conventional GSM mobile network.
"We call this a one-phone concept," says Westbrook. "In European markets, some mobile carriers offer low-cost or even free calls between users within a company, and competitive charges apply when calls are made outside."
Westbrook says HP calculates it has saved 38% of its telecommunications costs, through lower call charges and by rationalising the number of PABXs within its organisation.
A key element of the system is that all traditional PABX functions are still available via the single handset. Employees can make use of features such as automatic call-backs, call transfer and conferencing. The Ericsson system can be used with Sony-Ericsson's P900 and P910i smartphones or any other Symbian-based mobile handset.
While corporate PABXs are not expected to completely disappear any time soon, industry watchers agree that their days are numbered. The cost savings and flexibility offered by open, IP-based systems makes them a natural choice for the majority of organisations.
