The Caller ID and Its Audio Implementation

This paper firstly describes the basic principles of caller identification technology and analyzes several implementation methods, then puts forward a new audio implementation plan, and finally offers the hardware/software design of this plan.The caller identification is a new telecom service.The central switcher transfers the caller information including phone number via FSK to the reception terminal, and the reception terminal can acquire the caller information by demodulating the FSK signal.The caller information is usually displayed on an LCD screen, so the user has to step close to the caller ID screen to watch the caller information.To eliminate the inconvenience, we put forward a new caller ID solution, which speaks out the caller ID information.This design plan adopts the Microchip's PIC17C42A as a main control chip through which we implement the control of peripheral equipment.Compared to other similar MCU, the PIC17C42A has a FK(W15。40ZQ higher performance-price ratio, an easily developed RISC core and one-time programable technology, thus greatly shortening the developmental time.In the mean time, the caller ID reception terminal adopts Philips caller ID chip-PCD3316, through which the FSK signals will be converted into a binary data accepted by the MCU, then the converted data is transferred via I 2C bus line to PIC17C42A.In addition, this design plan also provides such functions as audio playback circuit, audio sampling circuit and dialing circuit to implement audio playback, sampling and dialing.The software system adopts a structural design method, thus sets up corresponding sub-programs.The main program can implement relevant functions by activating different sub-programs under the different active conditions.The caller ID equipment has the functions including caller recognition, saving, caller information speech notice, caller information search, deletion, dialing, record and playback.It can also save twenty caller phone numbers and eight caller names.With the development of telecom technologies and the increase of people's demand for telecom services, our caller ID equipment with speech functions will be more and more popular because it can satisfy many peculiar functions.