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Thread: help needed for Ht640 and ht648L RF encoder and decoder

  1. #1

    Default help needed for Ht640 and ht648L RF encoder and decoder

    I tried making the circuit given in

    i connected data in to data out directly (without RF module) to test the circuit.But it dosent works.I gave high input to TE ,then i gave high signal to one of the input pin , the VT pin of decoder becomes low from the default high. but output is not comming to the corresponding pin.
    I tried 390K resistors at osc pins also 1M resistor in encoder and a preset of 1M in series with 270K at decoder for tunning but it also dosent works
    can someone please advice me and help me to solve my problem


  2. #2


    Sorry, I cannot help you, but I needed HT series of encoder-decoder. Can you possibly tell me the source of (i.e. the place where I can purchase) these components and their price.
    Thank You

  3. #3
    Super Moderator T-1000 docel's Avatar
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    Sep 2005
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    Default ht

    1. At least 1 address pin and 1 data pin must be connected to true logic state. These must be the corresponding A and D pins for both enc and decoder.
    2. Maintain same Vdd for both.
    ^Anything is possible..
    after YOU prove it!!

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