Switching to voice over IP (VoIP) means less expensive management and maintenance for ThyssenKrupp Elevator's US telecom group, and it promises even more cost savings in the future for the lift manufacturer.

As its PBXs aged, replacing them with VoIP made sense on many levels, said Adam Kimball, the company's director of IT services.

So far adopting VoIP has resulted in a more flexible and fully featured call centre infrastructure that supports sales, service, parts distribution and help desk groups, he said. Over time, the VoIP network will also save on long-distance costs among the company's 160 offices.

The technology has enabled the distributed company to slowly migrate from traditional PBXs as each of its regions decides it's time to retire the old gear, Kimball said. In this way, it avoided a massive project to change over the entire phone system at one time.

The company has been eyeing VoIP products for more than two years, and three years ago switched to an MPLS fully meshed network service from Verizon. The idea was that MPLS could accommodate VoIP by having Verizon turn on quality of service and perhaps upgrade some network access lines, Kimball said.

ThyssenKrupp's old telecom infrastructure consisted of 60 to 70 percent Avaya PBXs, with most of the remaining gear made by Intertel along with keysets made by a smattering of other vendors. As each one reaches end of life, regional company executives decide what to do about replacing them, and so far all have bought into VoIP.

"We needed a system that would work at a single office, and if we never installed another system, it would still work at that office as a stand-alone phone system," Kimball said. "We also needed that single office to provide some of the wow features -- voice mail in your [e-mail] in-box, softphone capability, the call management platform, unified messaging."

On the administrative front, the major driver for VoIP was the ability to centralise telecom support and reduce the number of trips telecom staff had to make to branch offices, Kimball said. "That's difficult to do with a legacy PBX system," he added. "We had disparate systems and the support costs that went along with it."

Moving a phone could involve flying a telecom tech to a regional office, which is much more costly than having the phone moved and registering itself with the network as is the case with VoIP.

The business also wanted to standardise on a call centre platform. "We have multiple call centres and we wanted to create flexibility for that environment," he said. Two years ago when a hurricane threatened Texas, the company sent all the Dallas call centre staff to a Los Angeles office as a precaution. With VoIP, call centre traffic could have been rerouted to other offices on the fly using centralised VoIP management. Staff in those other offices could handle the calls, he said.

The company also wanted to establish four-digit dialling across the entire business, not just among offices served by the same PBX.

In addition, during outages, the VoIP network can reroute calls so the downed office doesn't lose connectivity, Kimball said.