1. A method of controlling an interface between a computer and a telephone line, comprising: providing an interface device between the telephone line and the computer; providing a set of commands readable by the interface device, said commands controlling operations performed by the interface device; dividing the commands into a plurality of categories, each category corresponding to a class of operations performed by the interface device and each command being included within a single category; selecting a command from a category of commands based on a desired operation to be performed by the interface device; and with the interface device, reading the selected command to initiate performance of the desired operation.