Imagine that a employee drove from home and made a call from their personal cell phone. That call travelled over the AT&T network, was paid for by the employee and used the 7 digit phone number on their cell phone. As the employee walked into a Beth Israel Deaconess building, control of the phone was transferred to the internal cellular system. Calls were routed through the PBX, the hospital paid for the calls via its negotiated rates, and standard hospital 5 digit dialing worked to and from the phone. Anyone calling the employee's desk phone was routed to the cell phone.
Ericsson discontinued its DWOS product as cell phone technology evolved to GSM/GPRS/EDGE.
Now, a new generation of products which converges fixed desk phones and mobile phones (called Fixed-Mobile Convergence) is emerging. The idea is similar to DWOS. Employees carry one device that serves as their mobile and desk phone. This one device is seamlessly integrated into the PBX. The infrastructure provides low cost voice connectivity while on campus by avoiding cellular charges. It's the Cool Technology of the Week.
There are two leading products in this space are (in alphabetical order, no preference indicated) Agito Networks' RoamAnywhere Mobility Router and DiVitas Environment Aware Roaming Technology
Here's how they work:
Nokia/Symbian phones (the only phones currently supported) run an Agito client which determines how best to connect to the Agito server that is connected to your enterprise PBX and your enterprise data network. Agito also interfaces to Cisco's Call Manager, providing device monitoring and management via the Session Initiation Protocol (SIP)
Windows Mobile or Nokia/Symbian phones run a DiVitas client which uses Environment Aware Roaming Technology to switch between a WiFi or Cellular carrier and connect back to a DiVitas server appliance connected to the enterprise PBX.
The technology is cool and promises one device connectivity, eliminating the desktop phone. The downside is that few handsets are currently supported (i.e. my Blackberry 8320 has WiFi and GSM/GPRS/EDGE but cannot run with Agito or DiVitas). Also dual mode phones really drain the battery when in WiFi mode.
This is a technology to watch, since I believe in a parsimony of gadgets. Getting rid of my desk phone would be great.