BT Fusion

In fact, the fixed portion of the link was provided by a Voice over IP implementation using the domestic ADSL service.

The same phone was used (a modified version of the Motorola RAZR or Motorola V560), but if the phone was within range of a special base station installed in the user's home or office then incoming and outgoing calls will be routed through that base station instead of the mobile network.

This link between the phone and base station was carried over Bluetooth (BT Fusion was latterly available using Wifi technology, thus allowing discounts not only at home but over BT Openzone WiFi hotspots).

Voice over IP protocols were used to transmit the call, but this was intended to remain largely unnoticed from the user's point of view.

[citation needed] Some commentators criticised the service as expensive and a "solution in search of a problem".