This project is a study about the telephone recorder with microcontroller in MCS-51 family doing as central processing unit for controlling the operation. It divides its operating into 3 parts as follows ; the first part is the data – receiving controlling from detector circuit, the second part is the data-sending controlling to computer units, and the part is the calculating of telephone service charges and can be driven out serial port through RS-232 to show its output on computer units, also can be printed from a printer. On every telephone call out, the recorder will record the starting time, the finishing time, the terminated line number or if the call-out phone is the other province line, it will show province in that area too. Moreover, it will show the rate of service charges when there is a dial eachtime, both in the area of the Metropolitant Telephone and the area of provinces.
By
Noppakun Wacharaporna
Somchai Tuenweeradech
