I don't have the data book handy, but I seem to recall that these chips used
different resistor values for the same clock frequency.  Try double checking
the chart on the data sheet to make sure they are running at the same speed.

Mark Walsh



Aaron Hickman wrote:

> To all,
>
>         I am attempting to use Holtek's HT-12D/HT-12E encoder and decoder
> pair for some basic RF transmission.  I have the chips on a prototype
> board and have gotten the encoder to transmit properly, but cannot get
> the decoder to work properly.  The strange thing is that when I feed the
> output of the encoder directly into the input for the decoder, I do see a
> high transition on the VT, valid transmission pin.  However, I do not see
> the any of the four data bits changing, regardless of their state.  Any
> clue or advice?  I have tried to contact Holtek via email, but so far no
> reply.
>
> Thanks,
>
> Aaron Hickman