Nokia and Alcatel are jumping the gun on Wi-Fi phones that work like regular office handsets: They're offering the same capability on ordinary mobile phones.

The advent of VoIP and IP PBX opened the door not only to business handsets that sat on a desk and sent packets around a wired LAN, but also to ones that could be carried around and use Wi-Fi. That can mean one handset for all business calls, anywhere in the enterprise, but that still leaves the employee's mobile phone for use outside. Dual-mode cell and Wi-Fi devices are just starting to emerge, and moving between networks raises technical issues.

By the end of the year, Nokia and Alcatel will offer software that makes Nokia Eseries mobile phones, a line of smart phones designed for business, talk to the Alcatel IP Communication server. That means they can be used like a PBX-connected desk phone, with features such as call conferencing and dialling by name, the companies said. It also lets employees keep their desk phones, use just one number, and program which device they want to receive calls on at a given time.

The system also lets mobile phone users tap into Alcatel's Least Cost Routing capabilities, which can cut enterprise long-distance charges, and make mobile billing records easier to find, they said.

The PBX features worked on mobile phones wherever they were used, and using the system didn't require any cooperation from the mobile operator a director of product marketing at Nokia, Tom Libretto, said.

In its first iteration, the Intellisync Call Connect for Alcatel software will make the phones talk to enterprise PBXes over the ordinary mobile phone network. In the near future, it would support dual-mode phones, the companies said.

Nokia acquired Intellisync last year to gain a better foothold in enterprises. It also weighed in to that market on the hardware side last year when it unveiled the Eseries phones, which include a variety of business features including QWERTY keypads and support for business applications and mobile email systems. Its E70 phone includes Wi-Fi as well as mobile radios.

Alcatel is near to closing a merger with Lucent Technologies and recently agreed to buy the Universal Mobile Telecommunications System (UMTS) business of Nortel Networks.

Nokia already offeredsimilar capabilities with Avaya and Cisco Systems PBXes, Libretto said. It planned to extend the Alcatel system to other Nokia phones.

Some features of office phones were already available on most mobile phones, and mobile-to-mobile calling plans could save enterprises money on calls between employees, Ovum analyst, Roger Entner, said. But having a desk phone and mobile phone with one number could be a convenient feature. For one thing, heavy phone users could avoid having to charge their mobile phones frequently.

Intellisync Call Connect for Alcatel is part of the Intellisync Mobile Suite from Nokia. It is set to become available through Nokia and Alcatel resellers in the fourth quarter. Pricing has not been set.