Love the Psion 3c I had but the case literally disintegrated. Had some type
of soft plastic that just corroded and fell apart.
On Monday, September 21, 2020, 03:24:59 PM EDT, [email protected]
<[email protected]> wrote:
The 5mx is a nice machine, I reviewed and tested several Psion devices. The
company was often said to be the UK version of Apple for their innovative
devices, programming language. I still have a soft spot for the series 3.
Sent from my iPad
> On 21 Sep 2020, at 8:10 pm, Jonathan Yuen <[email protected]> wrote:
>
> Hello,
>
> I actually am trying to connect a Psion 5MX with it's 'serial cable' to a
> raspberry pi, the serial lines on the GPIO thing. The pi is TTL, so I have
> an adapter to change it to RS-232. The adapter is DCE, but the Psion cable
> actually terminates as DCE, since it was made to plug into the serial port on
> your PC for synchronizing etc. The Psion has a perfectly good comm program,
> so I'm using it as terminal (there is even a VT100 program) but I need the
> 'null modem' or crossover connector to connect it to the level-shifter.
> Since they were both female, I actually did the test with 3 pieces of maybe
> 14 or 16 gauge insulated wire, maybe 3 cm long, with their ends stripped and
> pushed into the right holes. But I thought I should have something a bit more
> 'robust' and maybe do the other lines as well.
>
> I think Psion actually made a modem that connected to this cable, but that
> must have been DTE.......
>
> I guess I always thought of the 'modem' in null-modem as 'modem=DCE' since
> I've always connected DTE things together. But I appreciate the feedback from
> the group.
>
> Jonathan
>
> [email protected]
> ________________________________________
> Från: M100 [[email protected]] för Tom Wilson
> [[email protected]]
> Skickat: den 21 september 2020 20:18
> Till: M100 Mailing List
> Ämne: Re: [M100] definition of null modem
>
> "Null" means "none" or "zero." So "null modem" means "no modem."
> This term is an adjective and should be coupled with "cable", "adapter", or
> some other noun to be of any use.
>
> I don't see a need to re-define the term, since "null modem cable" is well
> established, and we all know exactly what the term means.
>
> Strangely, there are times you actually need a null modem cable to connect a
> computer to a modem. Most CP/M computers used dumb terminals, as did any
> mainframe and minicomputer (also called a mini mainframe.) Since those
> computers were designed to have DTE devices plugged directly in to their
> terminal ports, you might need a null modem cable to connect a modem to the
> mainframe... Of course, in that case, we'd just call those "modem cables"
> (or, more commonly, the 8-pin modular to DB25 adapter would be labeled
> "modem".) So in that instance, we literally used a null-modem cable to
> connect to a modem....
>
> Sometimes I love the English language.
>
> Tom Wilson
> [email protected]<mailto:[email protected]>
> (619)940-6311
> K6ABZ
>
>
> On Mon, Sep 21, 2020 at 9:16 AM Lee Kelley
> <[email protected]<mailto:[email protected]>> wrote:
> I've always thought "null modem" was a misnomer. It probably should have been
> called a "non modem cable" or simply a cross over cable as mentioned above.
>
> On Mon, Sep 21, 2020, 11:06 RETRO Innovations
> <[email protected]<mailto:[email protected]>> wrote:
>> On 9/21/2020 10:59 AM, Jonathan Yuen wrote:
>>
>> That said, I could only think that the other wiring should be same as a null
>> modem, but I thought that I should air my thoughts to see what other people
>> think.
>
> I'm curious about the use case, but you are correct, the wiring would be
> the same. Maybe, (though no one will do this, as the other terms have
> been in use for too long), it's best to call such a cable a "crossover"
> cable, like is available for Ethernet ports.
>
> Jim
>
>
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