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 <jonathan.y...@slu.se> 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 > > jonathan.y...@mykopat.slu.se > ________________________________________ > Från: M100 [m100-boun...@lists.bitchin100.com] för Tom Wilson > [wilso...@gmail.com] > 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 > wilso...@gmail.com<mailto:wilso...@gmail.com> > (619)940-6311 > K6ABZ > > > On Mon, Sep 21, 2020 at 9:16 AM Lee Kelley > <l...@3footed.com<mailto:l...@3footed.com>> 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 > <go4re...@go4retro.com<mailto:go4re...@go4retro.com>> 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 > > > --- > När du skickar e-post till SLU så innebär detta att SLU behandlar dina > personuppgifter. För att läsa mer om hur detta går till, klicka här > <https://www.slu.se/om-slu/kontakta-slu/personuppgifter/> > E-mailing SLU will result in SLU processing your personal data. For more > information on how this is done, click here > <https://www.slu.se/en/about-slu/contact-slu/personal-data/>
