Abstract: A method and apparatus for automatically modifying a dialled number into a standard international number before saving it in the telephone book, irrespective of the form in which the number is actually dialled. The number then stored in the telephone book is then stored in a form in which it can be dialled to make the required call from anywhere in the world.

Abstract: A GSM transceiver unit (10), for use in a GSM network (84), having a multilayer portable protocol stack is disclosed. The multilayer protocol stack includes a hardware layer (204), a first portable layer (206) configuring the hardware layer and controlling communications to and from the hardware layer, and second and third portable layers (208) controlling communications to and from the first portable layer and utilizing the first portable layer for communications with the GSM network. The GSM transceiver unit (10) includes a dynamics description (202) containing at least one time delay with each time delay representing an integer multiple of a fixed time duration for a particular instruction to be scheduled and containing at least one time advance with each time advance representing an integer multiple of the fixed time duration for a particular instruction to be scheduled.