Wayne, the attachment has showed up for me (using regular "gmail" web client). I'm not sure what part of the system here decides to filter out attachments. But to Mike, I wanted to report Thanks for the attachment, it did work for me at least.
Had an interesting talk with Usagi today around his LGP-21 (yes from 1963), debating whether the ASR-33 was RS-232 or not. He thinks not all ASR-33 were current-loop, but whether they were adapted after the fact, we're not sure (there was also KSR-33 and RO-devices). Also, today I discovered the world of early building security systems that used RS-232 to do biometrics (hand scanners of literal hands and such). -Steve On Sat, Feb 15, 2025 at 3:26 PM Wayne S <wayne.su...@hotmail.com> wrote: > I don’t see the attachment. > > Sent from my iPhone > > > On Feb 15, 2025, at 13:22, Mike Stein via cctalk <cctalk@classiccmp.org> > wrote: > > > > In the keyboard section of the attached document there are instructions > for > > testing with a terminal & USB>TTL RS-232 adapter. > > > >> On Sat, Feb 15, 2025 at 12:43 AM Steve Lewis <lewiss...@gmail.com> > wrote: > >> > >> Thanks, I had forgotten about the Kaypro. Looks like it uses a "custom" > >> 4-pin wire (one of them being 5V power). So just level-shift the TX/RX > >> pins through a MAX232 IC and it would talk to another R-232 system at > 300 > >> baud eh? Might have to seek out a lone Kaypro keyboard to give it a > try. > >> > >> I suspect some of the "serial style" mid-1980s IBM Model M keyboards are > >> similar. But I'm still wondering if anyone used this concept in the > late > >> 1960s - teletypes were expensive, flipping switches was tedious, so > >> keyboard alternates were hot items by early 70's (hence the TVT > popularity). > >> > >>> On Fri, Feb 14, 2025 at 5:28 PM Mike Stein <mhs.st...@gmail.com> > wrote: > >>> > >>> I believe that at least Kaypro used a TTL form of RS-232 for the > >>> keyboard; in fact, ISTR using an RS M100 notebook (+/- 5V) in place of > a > >>> keyboard in distant days. > >>> > >>> On Fri, Feb 14, 2025 at 12:27 PM Steve Lewis via cctalk < > >>> cctalk@classiccmp.org> wrote: > >>> > >>>> Rick Bensene: > >>>> > >>>>> I will try to find my Xircom parallel port Modem and Ethernet > adapters > >>>> in > >>>>> a box somewhere in my storage area and take a photo of them. If I > can > >>>> find > >>>>> them, I’ll post a link here to the photos so those in disbelief can > see > >>>>> them. > >>>> > >>>> > >>>> That'd be neat to see, if you do find the Xircom parallel modem. I've > >>>> seen > >>>> combo ones and their "parallel-ethernet" devices (which seem to go for > >>>> quite a premium these days), but not the modem only. Suppose they > >>>> weren't > >>>> too popular, as even laptops started to have built in modems. > >>>> > >>>> These days, I do use an SDLPT, that lets you use SD-cards to transfer > >>>> data > >>>> into a system over the parallel port. I suppose that's the same > general > >>>> principle (of read/writing one full byte at a time to a device). I > >>>> haven't measured its performance yet (but would characterize it as > being > >>>> comparable to a physical 3.5" floppy disk drive kind of performance - > I > >>>> think copying Quake took over 40 minutes, something like that; but I'd > >>>> like > >>>> to get more accurate about it, down to an actual bytes-per-second > rate). > >>>> Measuring that might give me an answer on how fast something like > >>>> Laplink/Interlink cable should be able to perform. > >>>> > >>>> As another experiment, I'll drop that ~7MHz 16550 serial card into a > 386, > >>>> and see if I can get a 386 to push data out on RS-232 faster than > 115200. > >>>> It should, but we'll see! > >>>> > >>>> > >>>> And I think I will do an RS-232 themed talk in June VCF, if a spot is > >>>> still > >>>> open - I think I have enough now to make it interesting. One area > I'm a > >>>> little stuck on is verifying that anyone actually did make an RS-232 > >>>> keyboard. Even for TV Typewriter, I'm not sure if I'd characterize > that > >>>> as > >>>> RS-232 related. And Gordon Bell integrated an ASR-33 (current loop) > to > >>>> the > >>>> PDP-1, but might not be accurate to call that RS-232 (but can't a > current > >>>> loop based thing be adapted to voltage?). I thought the POLY-88 > keyboard > >>>> was RS-232, but it'll be awhile before I can get back to that > equipment. > >>>> > >>>> > >>>> -Steve > >>>> > >>>> > >>>> > >>>> On Thu, Feb 13, 2025 at 6:32 PM Rick Bensene via cctalk < > >>>> cctalk@classiccmp.org> wrote: > >>>> > >>>>> Henry wrote: > >>>>> > >>>>>> I remember those, and when I went searching to look for more > >>>> information > >>>>> on them I found something I > hadn't stumbled on before - apparently > >>>> Xircom > >>>>> made a parallel port Ethernet adapter. It must have > >>>>>> been pretty painful. The parallel port wasn't a great high speed > >>>>> interface… > >>>>> > >>>>> ---- > >>>>> > >>>>> Yes, I have one of those parallel port Ethernet devices too. But, > >>>>> remember, back at that time, Ethernet was commonly 10Mb/Sec. I think > >>>> that > >>>>> 100Mb/Sec was only located in high-end datacenters and was very > >>>> expensive. > >>>>> For a laptop that didn’t have a PCMCIA port, and you wanted it on an > >>>>> Ethernet network, this was an acceptable way to go. Performance > wasn’t > >>>>> great, but most of the time laptops like this were used for TELNET > >>>>> connections to other hosts on the local network for “GREEN SCREEN” > type > >>>>> applications that ran entirely on the remote host. Performance in > such > >>>>> cases wasn’t nearly as much of a concern as it would be in the not > too > >>>>> distant future. > >>>>> > >>>>> I will try to find my Xircom parallel port Modem and Ethernet > adapters > >>>> in > >>>>> a box somewhere in my storage area and take a photo of them. If I > can > >>>> find > >>>>> them, I’ll post a link here to the photos so those in disbelief can > see > >>>>> them. > >>>>> > >>>>> -Rick > >>>>> > >>>>> > >>>>> > >>>>> From: Henry Bent [mailto:henry.r.b...@gmail.com] > >>>>> Sent: Thursday, February 13, 2025 3:54 PM > >>>>> To: General Discussion: On-Topic and Off-Topic Posts < > >>>>> cctalk@classiccmp.org> > >>>>> Cc: Rick Bensene <ri...@bensene.com> > >>>>> Subject: Re: [cctalk] Re: RS232 - parallel modems!? > >>>>> > >>>> > >>> >
