New batch of pdp8 OMNIBUS to USB interface! Please Read and react!

Philipp Hachtmann hachti at
Wed Feb 15 08:45:55 CST 2017

On 02/15/2017 03:40 PM, COURYHOUSE at wrote:
> I have not heard of  40 mil loop  here on ttys...   generally  20 mil or
> 60 mil.  - At  least  what   I have encountered. Is the 40 mil.  standard in
> Europe?

I have not heard about 60mA - at least not in the Telex network.
All mechanical 5 step teleprinters I have ever seen and owned run on 
40mA. And my test equipment has a mark on the scale at 40mA.
I thought that this is international. But I also know that with respect 
to teleprinters there are some CCITT norms that are internationally used 
- except for the US.
It starts with ITA2 code which is the official international 5-bit telex 
code. But US uses "US-TTY" which slightly differs.

Only the ASCII stuff (asr 33/35 etc) run on 20mA. But that's a totally 
different thing.

> Ed#  _www.smecc.org_ (
> In a message dated 2/14/2017 2:24:15 P.M. US Mountain Standard Time,
> hachti at writes:
> On 14.02.2017 22:18, geneb wrote:
>> On Tue, 14 Feb  2017, ben wrote:
>>> On 2/14/2017 6:27 AM, Alfred M. Szmidt  wrote:
>>>> FWIW, Mini-B connectors are on their way out, nor USB  OTG compliant.
>>>> Though agreed that they are flimsy... Why not  just a type A or
>>>> something? Easy, big, and  robust.
>>> Why not mini and regular?
>>>  Ben.
>>> PS: Add a 45.5 baud serail port. Control everything with  a  5 level
>>> TTY. :)
>> Dirty casual.  20mA  current loop or nothing.
> The 45 baud machines do NOT run on 20mA. They  usually run on 40mA :-)
> 20mA is the domain of model 28, 32, 33  etc.


Dipl.-Inf. (FH) Philipp Hachtmann
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Alemannstr. 21, D-30165 Hannover
Tel. 0511/3522222, Mobil 0171/2632239
Fax. 0511/3500439
philipp at

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