A FUNCTIONAL BLOCK HARDWARE ARCHITECTURE FOR SWITCHING SYSTEMS

In the proposed architecture, switching system hardware resources are allocated at the equipment level rather than at the component level of LSI chips. Equipment using these resources can thus be shared between independent systems. The efficiency of system development is improved by using structural elements called functional blocks (FBs). The hard ware in each FB consists of a shared part (a microprocessor, its perip heral circuitry, and memory) and a dedicated parr that implements the specific functions of the FB. Firmware loaded into the microprocessor consists of a shared part and a dedicated part that corresponds to the hardware parts. Each FB also has its own builtin autonomous testing f unction to test the reliability of that FB and has its own identificat ion function. By combining these FBs, this approach can flexibly cope with various switching system configurations for plain old telephone s ervice (POTS), integrated services digital network (ISDN), and broad-b and ISDN (B-ISDN). Tests using several types of FBs showed that the sh ared hardware and firmware parts of an FB can be shared between blocks . An architecture based on FBs results in a platform that can handle t he hardware for various systems, making it easy to construct new switc hing systems.