Working of HT12E Encoder IC

Pin Diagram of IC HT12E

HT12E is a 2^12 series encoder IC widely used in remote control and very common among Radio Frequency RF applications. This HT12E IC capable of converting 12 bit Parallel data inputs into serial outputs. These bits are classified into 8 (A0-A7) address bits and 4(AD0-AD3) data bits. Using the address pins we can provide 8 bit security code for secured data transmission between the encoder and the decoder. The encoder and decoder should use the same address and data format. HT12E is capable of operating in a wide Voltage range from 2.4V to 12V and also consists of  a built in oscillator. Let’s move into the working of HT12E encoder IC.


The pin Description of the IC HT12E was pretty simple to understand with total of 18 pins.

  • VDD and VSS: Positive and negative power supply pins.
  • OSC1 and OSC2: Input and output pins of the internal oscillator present inside the IC.
  • TE: This pin is used for enabling the transmission, a low signal in this pin will enable the transmission of data bits.
  • A0 – A7: These are the input address pins used for secured transmission of this data. These pins can be connected to VSS for low signal or left open for high state.
  • AD0 – AD3: This pins are feeding data into the the IC. These pins may be connected to VSS for sending LOW since it is a active low pin
  • DOUT: The output of the encoder can be obtained through  this pin and can be connected to the RF transmitter.


timing-diagram-ht12e-icHT12E starts working with a low signal on the TE pin. After receiving a low signal the HT12E starts the transmission of 4 data bits as shown in the timing diagram above. And the output cycle will repeats based on the status of the TE pin in the IC. If the TE pin retains the low signal the cycle repeats as long as the low signal in the TE pin exists. The encoder IC will be in standby mode if the TE pin is disabled and thus the status of this pin was necessary for encoding process. The address of these bits can be set through A0 – A7 and the same scheme should be used in decoders to  retrieve the signal bits.


Practical Application Circuit

The above diagram shows the practical set up of the HT12E encoder IC for better understanding on the working.

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Frank Donald

Frank Donald

Junior Network Engineer at Tata Communications
Frank Donald is an Electronics and Communication Engineer who loves building stuff in his free time. Video games, blogging and programming are the things he loves most
Frank Donald

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59 Comments on "Working of HT12E Encoder IC"

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biswanath hembrom

hi frank will the voltage in the encoder ht12e dout pin become zero if I unground the input data..plz reply thanks in advance


Hey Frank,
In the datasheet, it says that we can have 2^12 various combinations of addresses, which means 4096 different addresses we can make.
But pins AD8-AD11 are not address pins, so we have only 8 pins for address A0-A7, which can provide only 256 different addresses, so this IC is not good for production? is that right?


I have 5v 12d cut and 12v 12e ckt . for d i use 51k register and for e 1meg te going to high but data not working pls gaide me collect data


Calculating addresses, we are limited to 56 addresses per pair. Is that correct? if true, does it mean that we can’t use it for production? if true, is there any alternatives to get more addresses?


From a newbie:
Where are the input pins on the ic
I would like to connect a potentiometer to the input on the ic (for rc car)


Hi frank
thank you for time
i have problem with my project when i made saparate two bread board using arduino UNO by using ( RF Tx 433Mhz and Rx 433Mhz ) as wireless, then i wrote a code for arduino at least 10 line program then i used two IC HT12E for Tx and HT12D for Rx.
my equation are:
is the two ICs need a code?
please help me about that project


Hii Frank, I am interfacing 4 encoder with different address configuration.. In ht12d decoder section, i am changing the address by giving delay. But now, if i want to connect more than 4 encoder how do i configure data pins? I know i can give 2^7 different address. But if i want to transmit data in 5th encoder, in which pin of encoder sholud i provide data to encoder???


I have a doubt. Why do we put a resistor between two pins of oscillator 15 n 16 in ht12e


Dear Frank Donald
I appreciate your clear explanation of the HT12D & E working and using it for RF 433 Mhz transmission. I planning for dynamic addressing the HT12D and HT12E Ics by connecting the ULN 2803 output pins to the address pins of Encoder and Decoder ICs and control the address by Microcontroller. Will this work?

Request you idea on this.


So this IC encoding type is kind of OTP encoding, right?


Kind of. The differences between both is that the HT12E words, don’t have the 0101 at the end. So there’s no way to filter signals coming from other sources.