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New Link Updates online some time soon


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Hi folks,
It's been a while since I last posted to all you hyperboreans out there in telephone land, but nevertheless, I've been tinkering (read 'Linkering') at my workbench and I've got 2 new link designs to share with you some time soon.

The first one has been designated the "Link P" and the P stands for privacy. With the addition of a second bank of four relays (eg: for the Link 4+0 version) and some optocouplers, transistors etc., you can have total privacy on your Link around the house DTMF or pulse dialing intercoms. The ciruit allows for the first call to be established in total privacy, and if a second would be caller lifts their handset, they are returned 'busy tone' indicating that the Link P already has a call in progress.

The second design, called the "Link L" is designed for those of you who may have only one 4 wire telco cable running through your entire house/property, and it may well be that this cable is either inaccessible, or it may not be practical to install additional cables for extra handsets, without pulling half the roof tiles off, or jack hammering hald the slab foundation up. While the Link L uses party line for its internal conversations (as a matter of simplicity, there's no privacy on internal or external calls) it works well in either pulse or tone mode, and can still be effectively connected to an outside telco line (providing that this is street legal in your locale!!!)

Will upload circuits and text ASAP (my PC is off the air at the mo, but I can use op's until it's fixed) so keep your eyes peeled for these two new additions.

Austin Hellier
Downunder (but not out) 8)
email: [email protected] 8)

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  • 2 weeks later...

the Link P design has been finalised and those of you who are waiting in telephone land can be assured that it will work (I made it work reliably only last week!) and once again follows the simple design philosophy of simplicity and "off the shelf" components - no special chips or fancy and expensive relays.

The Link L will take a little longer to produce, as I always like to write my explanatory text while building and observing a working model. So when the Link P has been stripped off of the SK-10 panels, the Link L will take its place and go through the same test out procedure to ensuare that it will work reliably for those who need to build it.

Austin Hellier

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