[GreenKeys] Need PC to TTY Loop Keyer ASAP fast

[gil smith]

Hi John:

I just replied to Sellam -- didn't know it was the same project.

The TTY-Connect unit does NOT work with an externally-powered loop, since 
it has a built-in supply.

However, my old TTY-232-TAP gizmo does.  It also derives interface power 
from the 232 port, so read the notes to ensure that your port can be 
configured to set the needed lines appropriately.

The schematic is at:
http://www.baudot.net/gil/tty232-tap/TTY232_TAP.pdf
and the rest of the poop is at:
http://www.baudot.net/gil/tty232-tap/

The TAP can be set for a 20-mA loop, which is what I presume the M32 needs, 
and it has a bridge so you don't have to worry about loop polarity..

I can loan you mine (I only have one TAP built up), if I can find it.  I'll 
make sure it is configured for 20-mA and overnight it to you.

However, this is also presuming that your computer has a serial port that 
supports 5-bit mode (like most desktops).  You mentioned a laptop -- if you 
have been following the discussion of USB-to-232 adapters, I hope you 
realize that they will likely not work for an app like HeavyMetal.

If you are stuck with a laptop, an ascii-only USB adaptor, and therefore 
cannot use the TAP device, my only other suggestion would be to use a 
modified TTY-Connect that patches-out the low-voltage loop supply, to allow 
connection to an externally-powered loop.  I can probably do that for you 
as well, but you need to let me know, as my day is already hectic.

If you go this approach, the ascii-to-baudot conversion will be provided by 
the TTY-Connect, and the pc will talk to it in ascii mode at 
38400-baud.  This means you cannot use HeavyMetal (which talks baudot), as 
your pc needs to send ascii to the port.  You can simply use a terminal 
emulator (eg: HyperTerminal), and then just use the text-file-transfer option.

let me know,

gil


At 07:52 AM 10/4/2005, you wrote:


>   Further to yesterday's post re: making an ASR23 operate 'normally' for 
> a movie shoot in NY (Brooklyn) - is there anyone within the sound of my 
> keyboard who would be able to offer a suitable interface (Sale, loan, 
> trade, gift...) that would allow a PC, most likely a laptop, running 
> HeavyMetal - to key the loop of the Mod 32?  A loop supply is with the 
> machine, and has a dropping resistor for the correct current - we just 
> need the laptop to speak to the TTY. Perhaps someone has a nice 
> TTYConnect of Gil's that they could do without for a week or so....  or 
> any other RS-232 to current loop keyer....
>
>
>   And, (of course) this needs to be in New York and working tomorrow 
> sometime.
>
>
>   Anyone who might be able to be of (compensated!) assistance, please 
> write directly to Sellam, vcf at siconic.com ,  or myself - off-list please.
>
>   Thanks!
>
>  Cheers
>
>John   KB6SCO
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>GreenKeys mailing list
>GreenKeys at mailman.qth.net
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