OK…my TW523 two way power line interface arrived in the post this morning. This now allows me to connect my PC to the mains via the serial port (this sounds very dodgy!). Reading the blurb I am assured that the unit is “Opto-Coupled” which presumably means at some stage in the circuit the electrical connection is replaced by light to ensure the mains will never actually reach the serial port… The manual has some interesting technical data which I hope to OCR and put up here shortly.
So what am I going to do with my TW523? You may well ask! There are several software products that will allow you to use a just the PC and the TW523 to control X10 units. Laser kindly sent me a demo disk of one of them (HC2000) but it is a DOS product and pretty antiquated. I still reckon the JD TC+ or Stargate looks like my best option and for these to work you need a TW523 anyway so I won’t have lost anything.