[GreenKeys] Need PC to TTY Loop Keyer ASAP fast

Tue Oct 4 15:17:40 EDT 2005

The 32's usually needed a HV 20ma. loop. They didn't rellay
have a low voltage loop interface for the 32's since theye were
considered replacements for 15's and 28's in those days.

The 32 TELEX machines, as Don just pointed out, 
used external loops, often polar. But,
the correct polarity of a neutral loop will run a TELEX 32 just fine. 
As far as I know, only 33's and 35's (and 38's) worked with the 
20ma. low-voltage loop (around 24 VDC)..

Jack WA2HWJ

-------------- Original message from gil smith <gil at baudot.net>: -------------- 

> 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: Don Robert House 
> >Date: 10/04/05 12:12:45 
> >To: gil smith 
> >Cc: Sellam Ismail; John 
> >Lawson; 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 
> >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 
> > > _______________________________________________ 
> > > GreenKeys mailing list 
> > > GreenKeys at mailman.qth.net 
> > > http://mailman.qth.net/mailman/listinfo/greenkeys 
> > > 
> > > 
> > 
> > 
> > 
> >Vaux Electronics, Inc. 
> >480-354-5556 
> >(fax: 480-354-5558) 
> >www.vauxelectronics.com 
> > 
> > 
> > 
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> > 
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> > 
> >[] 
> > 
> 
> 
> 
> Vaux Electronics, Inc. 
> 480-354-5556 
> (fax: 480-354-5558) 
> www.vauxelectronics.com 
> 
> 
> 
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