The DS2143 is a comprehensive, software-driven E1 framer. It is meant to act as a slave or coprocessor to a microcontroller or microprocessor. Quick access via the parallel control port allows a single micro to handle many E1 lines. The DS2143 is very flexible and can be configured into numerous orientations via software. The software orientation of the device allows the user to modify their design to conform to future E1 specification changes. The controller contains a set of 69 8-bit internal registers which the user 1 of 44