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

dave.g4ugm at dave.g4ugm at
Thu Feb 16 01:28:56 CST 2017

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at] On Behalf Of Tony Duell
> Sent: 16 February 2017 06:29
> To: General Discussion: On-Topic and Off-Topic Posts
> <cctalk at>
> Subject: Re: New batch of pdp8 OMNIBUS to USB interface! Please Read and
> react!
> >> and 5 bit stuff almost unheard-of.
> >
> >
> > In the US, common for hams, not common for computers. Maybe they
> were
> > common for computers in the early 1960s.
> I think at one time radio amateurs (at least over here) had to use 5 bit ITA2
> machines for RTTY. It may even be to this day that RTTY implies that, and that
> ASCII is classed as 'data'. 

Yes RTTY is de-facto 5-bit. I have never heard plain ASCII being used on-air.  In its day AMTOR which uses 5-bit codes and adds error was also popular. The most common ASCII modes were AX25 and TCPIP over AX25.

> But the 5 level machines that were used over here
> tend to be Creeds (Creed 7s, 75s and 444s mostly).

I think it depends on "when". When RTTY first started Creed 7Bs were common cheap and had governed motors so could be adjusted to run on 45.5 or 50 baud. 
Later on 75's (which is my favourite) started to become available but many of these had synchronous motors so  could not be adjusted.
Finally 444's became available. I really don't like the 444 much. The typewriter style type basket seems to be a backward step over the neat single element of the 75...
I used a 7B with my "Newbear 7768"  6800 system.

> The RSGB (Radio Society of Great Britain, a bit like the ARRL) 'Teleprinter
> Handbook' (on RTTY operation) does have some details of things like the
> Teletype 28, so I guess some made it over here, but I've yet to see one.

I have seen a couple of 28s crop up on E-Bay and I am sure I have seen one "in the flesh" in some museum..

> >
> >> OK, we do see BRPE
> >> punches from time to time.
> >
> >
> > I'd really like to get one of those!
> I think shipping one is out of the question. Anyway, mine have 240V 50Hz
> motors.
> -tony


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