Abstract: A method for changing the call handling capacity of a telecommunications switch requires authorization from an external source, such as a telecommunications equipment manufacturing company (TEMC). Each switch purchased from the particular switch manufacturer includes a customized upgrade security protocol which limits access to data bus blocks associated with integrated digital carrier units of the switch. To alter the upgrade security program, an authorization code must be retrieved from the TEMC. The authorization code is then entered into the switch, and used to automatically alter the upgrade security protocol so that previously blocked data buses may be activated.