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12 Channel Encoder/Decoder?

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New Member
Where can i get an encoder and decoder which will allow me to control 9 or more channels?

I seen a holtek encoder/decoder pair but im not sure of the difference between adress bits and Adress/data bits It says its 12 bits but 8 are adress and 4 are data.

I need to be able to encode 12 switches and decode them also.

Is there another name for an encoder? Is a multiplexer and encoder? Can someone give me a really good explanation about encoders and decoders?

michael moon

New Member
the ht648 and the ht648l

the ht648 is a encoder chip , the address lines act as a coding system so that the decoding chip will only respond to the encoder ic, albeit , there are only 512 possible codes to cycle thru so don't go using this on something expensive , the ht648 does encode up to 8 switches to a serial stream with its code value , the chip you discussed only has 4 switch inputs ,
the difference between a multiplexer and a encoder is that a multiplexor is used to switch multiple singnals tru the same line by switching thru the singnals at least 10 times faster than the highest frequency your transmitting , the demux, or de multiplexor must then switch the same speed and in sync with the other end and the signals will come ou tthe same(ish) the other end . encoders are usualy for encoding data onto a serial or parralel bus ( this being a bus or a ir diode or a rf tx ) mostly they are used to trasmit data between one thing and another.
from what i have seen of the ht648 and the ht648l they are designed for remote controls usage , very low data rate , as in a yes i want to turn a light on or turn it off , they are not likely to work well with hundreds or thousands of switch combinations a second, namely a rf modem or a uP interface between cpu to cpu , if you want to do that then you would be well adviced to get a good book and study the subject in depth before trying to build this as it will most likely not work without a lot of tinkering.
good luck with your project , let me know if this answered your question and if you need any further info, if you let me know what it is your trying to make maybe i could offer you some ideas.


Well-Known Member
8 address bits will give you 0 to 255 storage locations. More than enough for what you are asking.
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