RE: Combining X10 powerline interfaces

["Kevin Hawkins" <lists@xxxxxxx>]

    I understood that basically the power line interfaces were akin to a modem in that they detected the presence of a single tone (120Khz) and could also superimpose this tone back on the power line upon request. In addition they reported the zero crossing points to allow you to time the insertion of the X10 carrier correctly.

 

    If that is correct then you can simply pass the received information from the line interface back to all connected units at the same time and unmodified which would be quite easy. Transmitting could be done likewise provided there is no contention. The problem comes with collisions and you would have to have some buffering available and the ability for the device to re-generate a timed transmission. Probably the best way would be to have an inbuilt decoder that stored the actual X10 command transmitted and then could recreate it - that way your internal storage is minimal. In fact - you could also then implement a repeater function in the same unit. Just thinking aloud here

 

    Li - any comments on the ON/OFF v just dimming LED operation of these things (see top post in thread) , could this be caused perhaps by the carrier being inserted abnormally late in the cycle rather than just after zero crossing and also there were some interfaces that didn't handle all the fancy X10 formats (extended, enhanced etc) I had an idea this was the the XM10U or is that basically dumb too ? - it may have been the CM11 I am thinking of...

 

    Kevin

 

 -----Original Message-----
From: K. C. Li [mailto:li@xxxxxxx]
Sent: 29 June 2002 12:42
To: UKHA Group
Subject: Re: [ukha_d] Combining X10 powerline interfaces

> On
> Sat, 29 Jun 2002, Kevin Hawkins wrote:
>
> >    
> Anyone think this is a worthwhile project and how many local
> interfaces
> > would you think makes sense ?
>
> It would be a
> challenging project to design and implement. The X-10
> two-way powerline
> interface is an elementary device that has little or no
> intelligence
> built
> in. The sending device connected to the TW523/XM10U
> needs to tell it
> exactly at what point in the mains sinewave to send the
> 120KHz signal in
> milliseconds and the duration. Likewise, the receiving
> signal from the
> TW523/XM10U is raw TTL signal that follows the waveform of
> the receiving
> X-10 signal. There is also the regular 50Hz (100Hz in
> effect)
> zero-crossing
> pulses available.
>
> The proposed device would have to emulate and
> provide
> the raw TTL signals
> to interface with all the attached equipment that
> are
> designed to work
> with TW523/XM10U in real-time and simultaneously.
> Presumably, the proposed
> device would also have to resolve collision
> problems between connected
> equipment.
>
> Regards,
>
> Kwong
> Li
> li@xxxxxxxLaser Business Systems Ltd.
> http://www.laser.com
>
>
> For
> more information: http://www.automatedhome.co.uk
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