In the past, when you call an office building or business, you would either be transferred to the department you want to talk to, or given their extension number. This extension is usually a 2-3 digit code that when dialed, transfers you automatically to the particular person or department you want to speak with. The reason why this code works is because it is programmed into a PBX system.
BT&T TELECOM GROUP CORPORATION is a Delaware, USA company incorporated in 1999. BT&T`s vision is to be a key player in the burgeoning telecom horizon, most especially in the Americas and Asia-Pacific countries.