Abstract: A communications system for routing calls originating in a cellular communications network of the system. A cellular communications device, e.g. a mobile telephone, appends a stored access code to a user-selected number and transmits the resulting modified number to the cellular communications network. The SIM of the communications device receives a user-selected number from a controller of the cellular communications device, appends the stored access code to the selected number, and returns the modified number to the processor of the cellular communications device for transmission to the network. The call is then routed in dependence upon the appended access code. The call can be routed to a routing switch when then determines an appropriate route for the call.