Subject: Re: Teletype

From: "Dwight K. Elvey" <[email-masked]>
Date: Tue Jun 3 09:29:35 2003

>From: [email-masked]
>
>> Whenever I type anything I just get a left-arrow. I am blaming the
>> 1818-23/-21 for this. Shouldn't I?
>
>Maybe. Does the Model 33 work correctly when switched to 'local'? If not, 
>then you certainly have problems in the Teletype. If it does work in 
>'local' mode, then you might still have problems in the Teletype, but 
>problems with the interface are also possible.

Hi
 It is also possible that he has the wrong speed gears/motor.
A 60Hz motor will run in local with 50Hz connected but the
Baud rate to the outside will be wrong.
Dwight

>
>> 
>> OK; current loop.
>> 
>> Would this explain a resistor (14 Ohm, big) in the slot of the KSR would
>
>Are you sure it's 14 ohms? I remember a multi-tapped power resistor with one
>tap being about 1400 ohms in the standard current loop electronics for 
>the Model 33.
>
>> get extremely hot when off this loop? Also; Hans Pufal, I would be most
>
>And I think it does run hot. When switched to local, the teletype is 
>_still_ a current loop device, but the transmitter (keyboard contacts), 
>receiver (the selector magnet driver -- the little module with 2 
>transsitors in the Teletype electronics chassis) and a 'local' power 
>supply (which includes that resistor) are all in series. A current loop, 
>but one entirely inside the Teletype Model 33.
>
>-tony

---

From: [email-masked] (Tony Duell)
Date: Tue Jun 3 16:12:12 2003

> Baud rate to the outside will be wrong.

That was one of the 'problems in the Teletype' that I was thinking of. I 
suspsect the easiest kludge for this these days is to fiddle with the 
clock at the computer interface end, and run the whole thing at 91.667 baud

-tony