Design of an ISDN terminal

This paper focuses on the design and implementation of an ISDN network terminal. This terminal can be used as a digital telephone with twenty different services. It is implemented with design restrictions of cost, dimension, power consumption and flexibility for future changes. The design uses an 8751 H Intel microcontroller as the main controller which handles both user end network interfaces. A Mitel 8930 SNIC is used as its ISDN "S" interface which handles HDLC protocol on D-channel. A Mitel 8995 D-phone is used for providing various telephone facilities. A DC to DC converter is designed for providing system power directly from the S-BUS.