Explain the working of broad band ISDN.

BISDN Configuration: Figure shows how access to the BISDN network is accomplished. All peripheral devices are interfaced to the access node of a BISDN network by a broadband distant terminal (BDT). The broadband distant terminal is responsible for electrical to optical conversion, multiplexing of peripherals, and keep of the subscriber's local system. Excess nodes concentrate some BDT's in high speed optical fiber line directed by a feeder point in a service node. Most of the control function for system excess is operated by the service node, as call processing, switching and administrative function and maintenance functions. All functional modules are interconnected in a star configuration and contain switching, gateway, administrative and also maintenance modules. The interconnection of the function module is demonstrated in figure. The central control hub serves as the end user interface for data traffic and control signaling maintenance. In essence, this oversees the operation of the modules.

FIG - BISDN Functional Module Interconnection

Subscriber terminal close to the control office may by pass the excess nodes completely and the directly connected to the BISDN network with a service node. BISDN nodes which used optical fiber cables can employ much wider band width and accordingly, have higher transmission rates and offer more channel handling ability than ISDN systems.