Intelligent voice dialing alarm system circuit diagram

Test probe P100-M3

Test - lowercase jpg

Kaixin micro test

This paper introduces the intelligent voice dialing alarm system with automatic dialing, detection and playback with AT89C5l single chip as the control core. The circuit structure and working principle of the automatic dialing and voice parts are mainly discussed. The main function of the telephone automatic alarm is: the user pre-stores the mobile phone number, the office phone or the alarm monitoring center's phone into the alarm host as needed. The alarm host continuously patrols the monitored devices (access control, smoke detectors, window magnets, cameras, etc.). When there are unsafe conditions (such as fire, illegal entry, video loss, etc.), the alarm host dials. The pre-stored phone number plays the corresponding alarm voice. If the phone is busy or unanswered, you can dial the next pre-stored phone number. If all the pre-stored calls are busy or unanswered, all pre-stored calls will be automatically redialed to ensure the validity and reliability of the alarm. .
DTMF transmit and receive circuit MT8880 and AT89C51 and voice circuit interface MT8880 is a special integrated circuit chip specially designed by MITEL to process DTNF signals. It not only has the automatic dialing function for receiving and transmitting DTMF signals, but also can detect the dial tone on the telephone trunk. Signals such as ring back tone and busy tone. Suitable for interface with single chip microcomputer, the peripheral circuit is simple. The MT8880 has five internal registers, which are the receive data register, the transmit data register, the transmit and receive control registers CRA and CRB, and the transmit and receive status registers. In this design, since only the transmit data register, the transmit/receive control register CRA, and the CRB are used to transmit the DTMF signal to implement the automatic dialing function, only these three registers will be described here. The data in the transmit data register determines the frequency of the dual tone signal to be transmitted, so only data can be written to the transmit data register. The two transceiver control registers occupy the same address, so the value of the register selection bit in the CRA is used to determine whether to operate the CRB. Its interface circuit is shown in Figure 4.

ISDl420 voice chip uses direct analog storage technology, and the recording and playback quality is excellent, and has a certain reverberation effect; its peripheral components are simple, only need simple resistance, container parts can form a simple recording and playback circuit; no backup Power supply, long information storage time, no need for dedicated programmer and voice developer; with strong location capability, the memory can be divided into 160 segments to manage, forming a minimum recording and playback time of 125ms. Its interface circuit diagram is shown in Figure 4.
Voice segmentation method: address input terminals AO~A7 are arranged from low to high, each address represents 125ms addressing, 160 addresses cover 20s voice range (160×0.125s=20s), recording and playback functions are from The set start address starts and the end of recording is determined by the stop operation. The end of the chip automatically inserts an end mark (EOM) at the end of the segment; while the EOM mark is played during playback, the playback is automatically stopped. In this design, because the four-stage alarm prompt voice is required, each voice is set to 5s in design, and the starting addresses are 00000000B, 00101000B, 01010000B, 01111000B, which can be seen from the starting address of these four segments. A7, A2, Al, and AO are all 0, so ground them.