[GreenKeys] Are my mails getting through?

[tony.podrasky]

Hi Bill;

Well - I don't know for sure - but usually that is used to
change the machine from duplex to simplex: simplex would be
when both the keyboard and printer are in the same loop. Duplex
would be the keyboard is in one loop and the printer in the other.

I had a 28-ASR that I took the keyboard out of the loop and built
an interface in the ST-6 so that I could talk to the ST-6 as if
the keyboard were an in-coming signal. This allowed me to also
talk to my SELCAL unit and switch the transmitter on and off as
well as turn on and off reperfs and T-Ds.

UE,
K2EAA - TONY
NNNN
ZCZC


On 08/27/2015 06:35 PM, drlegendre . wrote:
> I sent the following text yesterday, and surprisingly, it met no reply.
> Another member says it never showed up in his inbox.
>
> Did it make it to the list?
>
> -----ORIGINAL TEXT FOLLOWS----
>
> Howdy Gents,
>
> I'm just completing a scratch-build of an RS-232 / 60mA CL converter
> device as described on this page: http://www.aetherltd.com/connecting.html
>
> What is the purpose of the Keyboard Loopback terminals (pins 3 & 4) on
> connector J1?
>
> Pin 4 is a copy of the KB output signal on Pin 5, and Pin 3 is tied
> directly to the 120V DC supply, just downstream of the 2K 10W
> current-limiting resistor.
>
> As I see it, when the converter is connected, but idle, the current loop
> will be closed which would pull both Pins 3 & 4 down to roughly 3.3V DC
> above ground. This is assuming a 55R selector coil. When the loop opens,
> Pin 3 will rise to the nominal 120V DC supply, and Pin 4 will.. I don't
> know.. float? Show some high-Z voltage?
>
> So what's it all about, anyway? As ever, thanks in advance - your help
> is much appreciated.
>
> BTW - I used a very cheap & common 28V AC control transformer for the
> 120V DC supply. Running a standard voltage +tripler+ gives me almost
> exactly 120 DC with (what seems to be) very acceptable ripple at 60mA. I
> used 3X 1000uF @ 200V caps, but I'm sure it could be executed with caps
> of lesser value (and voltage as well). In fact, the ESR of the large
> caps may actually be a detriment to the tripler circuit - eh?
>
> -Bill
>
>
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