[GreenKeys] Need PC to TTY Loop Keyer ASAP fast

Tue Oct 4 14:55:08 EDT 2005

Hi guys:

I know very little about M32s, but if the "private-wire" CCU is similar to 
the M33, then it can be strapped for 60- or 20-mA.  Maybe for the baudot 
M32, 60-mA is the norm.  Never really thought about it.  I presume they 
still use the same basic electrical interface as the 33, at least in the 
private wire version.

For the ascii M33 private-wire CCU, 20-mA is the norm, and I believe that 
120V is the max loop supply for which they are rated.  In TTY-Connect, the 
HV loops use 160V, so I added a 25V LV loop for the M33 (HV not needed, LV 
is safer, less heat, cheaper...).  I presumed this would also be the loop 
of choice for the M32.  The LV loop resistors are sized for 20-mA -- I 
suppose the resistors could be changed for 60-mA, but I presume that the 
M32 CCU would also have an option to go to 20-mA.

I don't know anything about the M32's telex CCU, except that some folks 
have told me it can be hooked up to be driven by a 20-mA loop.  Dunno 
how.  Jack?

Off the top of my head, I don't know of any other M32 CCUs, but perhaps 
there are more.  As far as I know, the private-wire CCU is the same as the 
M33, which has a built-in loop supply for local operation, but line 
operation requires an EXTERNAL supply.

I am not certain what kind of CCU is in this NY unit, or whether it really 
has a built-in loop supply for line use.  Also don't know if it is 20- or 
60-mA.  Or telex.  Or something else.  Kinda need to know this to move on.

gil

At 10:31 AM 10/4/2005, you wrote:
>I have been running my 32's daily for two years with a 60ma loop supply of 
>120VDC
>Wayne  wb0cte
>
>-------Original Message-------
>
>From: <mailto:drhouse at nadcomm.com>Don Robert House
>Date: 10/04/05 12:12:45
>To: <mailto:gil at baudot.net>gil smith
>Cc: <mailto:vcf at siconic.com>Sellam Ismail; <mailto:jpl15 at panix.com>John 
>Lawson; <mailto:greenkeys at mailman.qth.net>greenkeys at mailman.qth.net
>Subject: Re: [GreenKeys] Need PC to TTY Loop Keyer ASAP fast
>
>Not sure about 20 mils at the line cord.  When we helped film FOG OF
>WAR both model 32s were former TELEX machines.  Neither had their own
>power supply, except for the off normal dial supply.  I ran both line
>cords in series with a Navy surplus rectifier set at 60 milliamps.
>Maybe just my ignorance of TELEX machines but the 32ASRs both ran
>just fine.
>
>Don
>
>
>On 4 Oct 2005, at 10:29 AM, gil smith wrote:
>
>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>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/>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, 
> <mailto:vcf at siconic.com>vcf at siconic.com ,  or myself - off-
> > list please.
> >
> >   Thanks!
> >
> >  Cheers
> >
> > John   KB6SCO
> > _______________________________________________
> > GreenKeys mailing list
> > <mailto:GreenKeys at mailman.qth.net>GreenKeys at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/greenkeys
> >
> >
>
>
>
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>480-354-5556
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>
>
>
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