athe remote control function to the office workers bring a lot of work and life easy . I have a function of the hands of just slightly different from the above article "telephone remote control pickup" in the devotion to the reader.
  I. Features
  1. Remote control for home appliances, power.
  2. Remote control of electrical power, delay shut down automatically.
  3. Remote or local change passwords, the number of rings simulated hook all the settings and remote control functions.
  4.2 Road contact output (connect 220V power outlet), 1 DC output (12V), 1 Road level output (including positive and inverting two outputs for direct connection of the relevant electrical control side).
  5. Has a second feature set, an increase of remote pickup function.
  6. Remote operation are the state tone.
  7. The working status of all the settings after power, data storage (100 years) is not lost.
  Second, the circuit works
  Telephone remote control pickup circuit diagram, such as photos.
  IC3A, DW1, R7 form hook telephone line ring signal detection and line detection circuit. Normal telephone line so DW1 breakdown voltage, optocoupler input current is small, to ensure that the output low signal output, P3.0 is pulled down into the low, the main task is to monitor the microcontroller at this time the voltage changes P3.0 .
  In parallel with the telephone when the telephone remote control or telephone remote control pickup hook ring signal is received, and the required number of rings, the phone pick up the remote control simulation, the voltage on the telephone line from 48V down to 7 ~ 8V . At this point DW1 deadline, P3.0 is the internal pull-up resistor pulled high. SCM test to P3.0 is high, open the external interrupt 0, P3.2 receiving IC1 (8870) issued by the strobe, strobe when it comes time to receive the 8870 microcontroller data ports {11} ~ {14} Two feet audio signal data.
  If the telephone line ring signal appeared, 90Vp-p of the ring makes IC3A output voltage by the ringing frequency on and off. P3.0 output from the high signal detected IC3A start automatically determine the signal, or pick up the ringing signal. 25Hz square wave of the real ring signal, ring signal MCU after the end of each number of rings counted and the number of rings in the data and set the counter ringing off hook data comparison, the two are equal, P3 .1 set to low, transistor V1 through IC3B driver for analog hook. Analog hook, the calling party can hear remote pickup three times in the ring issued P3.1 tips. Caller for a password, telephone remote control pickup of the password for authentication. The password is correct tone adopted by the issue of verification; password is not correct is not issued by the tone, and allows the caller to re-enter the password. The second password is correct, enter the back of the program, two passwords are not correct, the phone hang up the remote control. Caller the correct password, they can remote telephone keypad, enter a different number for remote control, complete control of different tasks.
  IC1 double on the telephone line to receive the audio signal, and convert the data to the microcontroller. IC1 3.579545MHz crystal clock signal using the microcontroller's clock signal is also output from the oscillator IC1.
  IC6 X25045 is the EEPROM circuit that includes watchdog and voltage monitor. The circuit with the 89C2051 with only solve the set of data after power off to keep the issue, but also resolved to set the program running out of data reduction, low-voltage detection data protection issues. Combined microcontroller and external circuitry associated I / O port using optical isolation, greatly improved anti-jamming capability of the microcontroller, to ensure reliable operation of the circuit.
  IC6 and IC1 enable control by the microcontroller. Normal working hours, IC1 and IC6 will not work simultaneously, so the two circuits can share the data lines I / O port.
  MCU P3.4, P3.5, P3.7 of the control of a relay circuit to control the supply of household appliances. Control of the microcontroller output pin and the relay between the two transistors with isolation, amplification, pre-transistor is used to reverse-phase, after the transistor-level work to promote the relay. Work relay separate ways, that is, telephone remote control operation by the user and the feature set to decide.
  The first relay can be done through the remote on or off in different keys, you can also remotely turn on (power), and enter 3 digits, set the delay time 001 ~ 999 minutes after the close.
  In addition to the second relay of different keys by remote control on or off, there is also the second feature set. The second feature set, the working status of work by the telephone line state to decide. Under normal circumstances, the second output power condition; when the telephone line voltage is lowered due to hook, pull the relay for 1 second delay, the output power state; hook telephone line is detected (line voltage recovery 48V) after , delay 3 seconds automatically stops power supply. This feature is usually the automatic power supply for communication equipment. For example, in a telephone line connected with telephones and fax machines to telephone-based, also often used in fax machines, requires the use of fax machines in time when you receive or send faxes. At this point, with the second way to control a socket, the power supply as a fax machine. Fax machines do not usually supply, send a fax, the fax machine pick up, phone line voltage drop, fax machines automatically power, as with the original fax operation. Outside call, the phone ringing, the called hook, fax supply, when the other person asked to send a fax, press Fax Start key to receive faxes. In this way, you can easily receive and send faxes, but also ensure the normal telephone line call. By setting appropriate remote pickup analog phones ringing off hook, and also to ensure the long-range remote operation of other electrical equipment.
  The third relay is the one-shot output, remote speed control. Press the action button, relay, output 12V DC, 1.5 seconds automatic reset time delay. The third road is mainly used for opening and closing control of electronic door locks, electronic locks, such as control of the garage.
  The fourth way is to level out, there are both positive and negative phase outputs for level control of some direct control of home appliances.
  V7 and surrounding components form amplifier, working state by the microcontroller. Usually P1.0 is high, amplifier circuit can not build a normal operating point, there is no zoom capability, the surrounding environment does not send the sound to the telephone line. P1.0 down as low as when the amplifier circuit into a normal amplification status, MIC1 receiving ambient sounds and converted into electrical signals, amplified by C10 to the V7. Select the resistance resistor R15, so IC4A work online work status, V7 output audio signal through R30 and C2 coupled to the IC4A's input, the output audio signal output directly added to the base of V1. V1 R19 to adjust the working point in the amplification by the state, the audio signal is amplified by V1 emitter, the output to the phone line straight to the caller. Caller listening time 1 minute 20 seconds into listening, stop for 5 seconds, and then listen for 20 seconds, stop for 5 seconds, the end of the last 10 seconds and the listener hanging. Stopped within 5 seconds of listening through the telephone keypad can also be discharged, or continue to monitor the working status of the 4-way control. In the non-monitoring state, within 20 seconds if no key operation, remote pickup automatic hang up.
  3 circuits relay contact output, the fourth road level output are output with a terminal block, control line can be directly and reliably with the terminal connection. AC output for the contact (switch), not a series line, the output is not charged, the use of safe and reliable.