GE’s Electro Code 5 combines the industry’s foremost signaling principles with state-of-the-art electronic technology, bringing packaging, electronics and software together in an easy-to-install, application-flexible system. The heart of the system is a vital peripheral master processing module with two processors for vital application processing and a processor for diagnostic and serial communication interface. A control display unit (CDU) is the local interface to the EC 5 system, usable as a hand-held device and removable for use with other EC 5 equipment.