About a possibility of designing a command unit of a low capacity electronic telephone exchange with temporal switching using INTEL 8752 microcontroller

The work describes the manner in which the command unit, equipped with an INTEL 8752 microcontroller, manages the hardware resources of a low capacity electronic telephone exchange with temporal switching, consisting of the interface to the external medium, the temporal connection network and the tones machine. The use of the INTEL 8752 microcontroller offers the following advantages: small volume, high reliability, low consumption, low price. From the exchange presented, one module was built, including 16 individual subscriber circuits, and 4 junction circuits from the interface with the external medium, the temporal connection network, the tones machine which includes the system for transmitting vocal messages and the command unit equipped with a microcontroller for managing these resources. The hardware structure of this exchange is minimal and meets all the standard requirements. The command program was written for performing automatic local, outgoing and also incoming telephone links, along with several telephone services such as: call redirecting, busy override, exact time call, call restricting, vocal information services etc