Abstract: The disclosed microprocessor support system provides a total "laboratory" environment for developing and testing application software as well as for debugging the microprocessor-based application machine itself. The microprocessor support system contains a time shared minicomputer equipped with a full set of peripherals which functions as the main or operating system. A data link connects this operating system with test equipment located at the site of the application machine. This test equipment consists of a field test unit which provides an interface between the application machine, a local keyboard terminal and the operating system such that an engineer at the site of the application machine has access through the field test unit to both the microprocessor-based application machine and the operating system with its sophisticated hardware and software resources to assist in developing and testing application software, as well as debugging the application machine itself.

Abstract: A communication system call transfer arrangement is disclosed which relies on the establishment of two system access buttons on every telephone served by the system. The system access buttons are operational to originate a call to any station in the system over any idle link. A call on either access line can be added to any other currently active line on the telephone set. The system access buttons at all the stations operate such that an incoming intercom call will terminate on eitherbutton, and calls can be originated from the station by using either button. For call transfer purposes the system access lines are arranged such that when the station passes a call via the access line to another station and then goes on-hook, the system access lines become idle and are available for use by the station even while the transferred call is in progress.