1. A communication system comprising a communication device and a communication terminal; the communication terminal having access to a database to query data relating the communication device; the data comprising invocation instructions for invoking at least one function of the communication device; the communication terminal comprising means to cause output, at the communication device, of data representing operator instructions, associated with the invocation instructions, comprising prescribed user input actions to be performed to invoke the at least one function of the communication device; and means to compare, or to enable comparison of, data representing actual user input actions, performed following output of the data representing the operator instructions, with the invocation instruction data to determine if the at least one function of the communication device has been invoked.