>>>>
tin...@isbd.co.uk wrote
>>>>> I don't think that works does it? Apart from anything else an EOR
>>>>> gate only has two input, I'm looking for (possibly) three or more.
>>>>> The EOR approach will work for a two way switched light I agree.
>>>> True, I am not aware of a chip that has a multiple input XOR but
>>>> something like a 7486 has four two-input XOR gates that can be
>>>> cascaded. Two inputs into the first gate, another two inputs into
>>>> the second. The outputs of gates one and two into the inputs of
>>>> gate three. The output of gate three will be high if there are an
>>>> odd number of the four inputs high which satisfies the OPs
>>>> requirements.
>>>> Output of three could be connected to one of the inputs of four
>>>> and the other input connected to another switch if five inputs
>>>> where required.
>>> A parity generator chip is simply a multiple-input exclusive OR
>>> gate, e.g. the 74280 9-bit Odd/Even Parity Generator is basically a
>>> 9-input XOR gate (with an additional second inverting output).
> Actually, just to clarify, a parity generator is not simply a
> multiple-input exclusive OR, but it is what you are after for
> this logic case.
>> Is there not a way to do this using X10?
> You could get X10 into the solution if you wanted to.
In fact any X10 light can have as many switches as you like with no special treatment.
You can kick yourself now.