Re: TI-H: My TI92 Hardware Homepage : RTLink?


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Re: TI-H: My TI92 Hardware Homepage : RTLink?




From: Christian Auer <ca1@gmx.net>
>My TI92 Hardware Homepage has been updated...
>http://members.xoom.com/Ti92/index.html


You mention on the radio link page that you don't understand some of the
symbols used in the schematic, like which ones?  He is using those little
trapezoids for transistors and in one place he has a cap drawn with the
gap filled with slanted lines.  Not sure what that means.

I have three questions about this circuit.  I'm no EE, my electronics skill
doesn't extend much above the basics, so I may be totally off, but a couple
of things looked a bit strange to me.

First, and this is a big one, there is no indication that the separate power
supply for this thing has a common ground with the calculator.  He
explicitly
mentions that the link's ground cable is not to be connected.  That means
that 5v on the red wire (relative to to the calc ground) isn't necessarily
5v relative to the RTLink's ground.

Second, the white wire is connected directly to battery negative ?? Doesn't
that make it kind of hard to send half of the bits and ack the other half?
I don't see how the RTLink can ack any bits received from the calc.

Third, well, I forget what the third was, but last I knew there was no
working
radio link (other than perhaps Grants, but I haven't heard of anyone else
who has successfully built that).  Is this one of the hoax plans, or does
this thing really work?

DK



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