22. A method comprising: encoding message transfers between an input/output controller of a modular communication apparatus and a processor of a modular communication apparatus, which provides a routing function, using a predetermined markup language comprising tags, using a structure of the predetermined marked-up language for communications between the processor and an application hosted by the processor, using messages having the structure of the predetermined markup language for communications between applications hosted by the processor, via the processor, wherein each message includes a destination tag which provides an indication of a destination of the message, and causing routing of each message to its destination using the routing function and the destination tag, wherein the processor is configured so that messages transmitted between applications, via the processor, are transmitted within the modular communication apparatus.
23. A method as claimed in claim 22 wherein the routing function is operable to use information stored in a database.