Hello, I'm not that allergic to videos but I have trouble sorting them. The tech-related stuff has a whole spectrum from simple to complex.
I did look at some youtube things but I wasn't sure which video you are referring to. Jonathan [email protected] ________________________________________ Från: M100 [[email protected]] för [email protected] [[email protected]] Skickat: den 22 september 2020 20:29 Till: [email protected] Ämne: Re: [M100] definition of null modem Well maybe hold off then, because my plan is to document what I do. I don’t mind videos but there is a reason I maintain a tech blog for all the project I work on / build. Sent from my iPad > On 22 Sep 2020, at 7:11 pm, Jonathan Yuen <[email protected]> wrote: > > Hi, > > I'll have to take a look. Generally avoid videos because I'm too lazy to > take notes but I realize that recording a video is easier than writing stuff > and making web pages..... > > Jonathan > > [email protected] > ________________________________________ > Från: M100 [[email protected]] för [email protected] > [[email protected]] > Skickat: den 22 september 2020 10:54 > Till: [email protected] > Ämne: Re: [M100] definition of null modem > > Buddy > > Have you checked out youtube? I’m literally about to undertake a project that > sounds like what your after. I’m fitting a rpi zero into an old modem housing > and having it share the WiFi out over ppp serial. There are two very good > videos on this process which can be found on YouTube. One uses an Commodore > Amiga and the other is using a Win95 PC as the system they are trying to get > online. Both see the Rpi as a regular modem. > > I hoping to get it working so I can recover email on my Amiga 500+ > > Sent from my iPad > >> On 22 Sep 2020, at 9:41 am, Jonathan Yuen <[email protected]> wrote: >> >> Hi, >> >> I have an FTDI converter, bought it to connect the M100 to modern stuff >> without real RS232 ports. But I was trying to get ppp to work on the >> PI-Psion connection and I was trying everything possible (and it still >> doesn't work) under linux. I can get it to work on Windows but that sort of >> defeats the whole purpose of having something small bridge between the Psion >> and today's internet. I really only wanted to get mail to work so I didn't >> have to type on the phone or tablet screen but maybe a small bluetooth >> keyboard is the answer. If I keep the mail on the pi I guess I can use any >> terminal to do mail, like the M100 or the Psion but the M100 keyboard is >> better. >> >> How to configure ppp to work is still a mystery but that is really not the >> subject of this list. Tried slirp and even found a number of people that >> claimed it would work but it doesn't work for me and it doesn't want to >> compile on my linux machine, either. >> >> Jonathan >> >> [email protected] >> ________________________________________ >> Från: M100 [[email protected]] för Tom Wilson >> [[email protected]] >> Skickat: den 21 september 2020 22:06 >> Till: M100 Mailing List >> Ämne: Re: [M100] definition of null modem >> >> Some tips on that.... >> >> Are you using Linux on the Pi? If so, it would be easier to just use a USB >> serial port. The Prolific and FTDI ports both work with Raspbian; I've used >> both. >> >> Otherwise, maybe look at a DTE wired level converter with CTS/RTS.... like >> this one: >> >> https://www.amazon.com/NulSom-Inc-Ultra-Compact-Converter/dp/B00OPU2QJ4/ref=sr_1_4?dchild=1&keywords=ttl+rs-232+level+converter&qid=1600718673&sr=8-4 >> >> Although I'm not sure where you'll get CTS and RTS on the Pi. I don't know >> that it's mapped to any of the GPIO pins. This might help a little bit: >> https://www.raspberrypi.org/forums/viewtopic.php?t=241623 >> >> >> >> Tom Wilson >> [email protected]<mailto:[email protected]> >> (619)940-6311 >> K6ABZ >> >> >> On Mon, Sep 21, 2020 at 12:10 PM Jonathan Yuen >> <[email protected]<mailto:[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]<mailto:[email protected]> >> ________________________________________ >> Från: M100 >> [[email protected]<mailto:[email protected]>] >> för Tom Wilson [[email protected]<mailto:[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]><mailto:[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]><mailto:[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]><mailto:[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 >> >> >> --- >> När du skickar e-post till SLU så innebär detta att SLU behandlar dina >> personuppgifter. 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For more > information on how this is done, click here > <https://www.slu.se/en/about-slu/contact-slu/personal-data/> --- 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/>
