Abstract
M.Sc.
The work is based on a project done by SAMES (South African Micro Electronic Systems) for the local production of an integrated circuit that previously had to be imported. The circuit finds application in the telecommunications field where it controls loop disconnect dialling in the telephones. The mechanical disc dial is thus replaced by an electronic network that makes use of push-button entry and full digital out-dialling. The push-button telephone is compatible with the rotary disc dial telephone with
advantages in reliability, speed and ease of use. An access pause and re dial facility add towards a more efficient telephone. The circuit was bought from an American company for manufacturing purposes. A process fit and circuit modifications were done for product ion on the CMOS process line at SAMES. The work includes a circuit- and process study with modifications, computer aided design, prototype production and analysis. The original circuit is called the General Instruments AY-5-9151D and the re-designed version the SAMES SA 9151-A2.