test-drb September 2002

test-drb@ccmp.vtda.org

217 participants
408 discussions

by tothwolf＠concentric.net

I guess this is only slightly OT, since this particular recorder dates >from around 1948-1950 ;) I managed to rescue a Webster Chicago model 79 wire recorder from a shelf that was overlooked in my friend's shop after most of it had been dumped into the dumpster. The model 79 was sold as a bare-bones unit without any audio circuitry, while the model 80, which used the same mechanism, was a complete unit. A little more info about Webster Chicago wire recorders can be found at [http://www.rci.rutgers.edu/~dmorton/webcor.htm], and more info about wire recorders in general can be found at [http://www.rci.rutgers.edu/~dmorton/wire_recorders.htm]. The audio circuitry that my friend built for this model 79 appears to be long gone, so in order to play back the 3 reels of wire I also rescued, I'm going to have to recreate it. I managed to found the instruction manual in a binder in the dumpster, but I don't have a service manual (though I'd certainly like to find one). The instruction manual covers the use of the model 79 and a basic design for the audio circuitry. If anyone else has a model 79 or 80, or thinks it might otherwise be worthwhile, I'm willing to scan the manual if someone has a place to host it on the web. -Toth

22 years, 3 months

EIA 232 vs. 422, Color Computers (was Re: Serial floppy drives)

by dwightk.elvey＠amd.com

>From: "Gary Hildebrand" <ghldbrd(a)ccp.com> > >Eric Smith wrote: >> >> > <snip> > Connecting EIA-232 directly to EIA-422 could let the smoke >> out of something, and we certainly wouldn't want that. >> > >ISTR that 422 was simply a balanced line version of 232. I think you >can just tie to the non-inverting line and ground and make it work. >Unless there's something else needed. > >Gary Hildebrand >St. Joseph, MO > NO!!!! RS-422 inputs should not normally excede 7V. Many RS-232 are driven with 12 volts. Also, RS-422 is offset above ground and not intended to take large swings below ground. Most RS-422 receivers do not include ground as part of their common mode operation, so you can't tie one input to ground and get it to work. Dwight

22 years, 3 months

also interesting on eBay

by pete＠dunnington.u-net.com

On Sep 6, 7:07, Andy Holt wrote: > another item on UK eBay may also be extremely interesting ... if rather > expensive: > http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=2051100106 > is a BBC Domesday setup in (mostly) working order. AFAICS the only notable problems are the scratch on the video montage disc, which might be less of a problem if the buyer solved the other problem: lack of the remote control. The remote is only used to skip through the montage (which is one of four sides), it's not used for anything else, so it's not a big deal. However, I'll make the same offer I made to the BBC mailing list when it appeared there: if the winning bidder is a list member, contact me, as I think I have a spare remote for the player. I may also have a manual (but probably not the complete set). BTW, the seller appears to have the other two interactive discs that were released for the system, in his other auctions. Of course, the LaserVision player will play "ordinary" LaserVison video discs as well. -- Pete Peter Turnbull Network Manager University of York

22 years, 3 months

[jpadilla@students.uiuc.edu: Re: p.s. Re: card reader (fwd)]

by dtwright＠uiuc.edu

Hey everyone, This is a request from someone in Aeronautical Engineering at the University of Illinois. If you think you can help him out, please contact him directly. Thanks, Dan ----- Forwarded message from "Jose F. Padilla" <jpadilla(a)students.uiuc.edu> ----- Date: Tue, 3 Sep 2002 17:29:20 -0500 (CDT) From: "Jose F. Padilla" <jpadilla(a)students.uiuc.edu> To: Dan Wright <dtwright(a)uiuc.edu> Subject: Re: p.s. Re: card reader (fwd) Dan, a shoe box full of 80 column punch cards containing an old FORTRAN code would be converted to an ASCII text file. Thanks. -Jose >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< Jose F. Padilla, Research Assistant and Graduate Student Department of Aeronautical and Astronautical Engineering University of Illinois at Urbana-Champaign Work: 217 244 1447; Base: 217 377 7310; Christ Delivers >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< >=< ----- End forwarded message ----- - Dan Wright (dtwright(a)uiuc.edu) (http://www.uiuc.edu/~dtwright) -] ------------------------------ [-] -------------------------------- [- ``Weave a circle round him thrice, / And close your eyes with holy dread, For he on honeydew hath fed, / and drunk the milk of Paradise.'' Samuel Taylor Coleridge, Kubla Khan

22 years, 3 months

IBM Aptiva for parts

by SUPRDAVE＠aol.com

In a message dated 9/4/2002 8:41:34 PM Eastern Daylight Time, rschaefe(a)gcfn.org writes: << Move-out week is over on campus, but I decided hit a couple of alleys on the way home anyway. The only thing of interest I found was a skinless, stripped Aptiva that I nearly passed up, but then I noticed that the slots were on an active riser card so I picked it up anyway. The power supply has some extra wires on it, too. I figure these are odd enough to be hard to replace if you get a bad one. If anyone wants the parts for $postage, let me know. I've got: >> is there a machine type/model number listed anywhere? sounds like a 2168-??? model. -- Antique Computer Virtual Museum www.nothingtodo.org

22 years, 3 months

DEC T-11 evaluation board (attn: Tony Eros)

by mbg＠TheWorld.com

I haven't received my board yet (I bought the third one of them that was up at auction on ebay). Wehn it comes in I will be very interested in learning how to operate it and maybe get something running on it... Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | email: gentry at zk3.dec.com (work) | | Unix Support Engineering Group | mbg at world.std.com (home) | | Hewlett Packard | (s/ at /@/) | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 (DEC '77-'98) | required." - mbg KB1FCA | +--------------------------------+-------------------------------------+

22 years, 3 months

OT Housecleaning -- Hazeltine 1552 terminal

by zaft＠azstarnet.com

I have an old Hazeltine 1552 terminal with docs that I need to get rid of, I am cleaning house. IT DOES NOT WORK, as far as I can tell -- screen powers up filled with junk. It's probably fixable to those that are handy with such things. Anyway, anyone wants it and is willing to come get it or pay for shipping, it's yours, otherwise it goes to the recyclers next week. I'm in Tucson Arizona. Please respond offlist. Gordon Gordon Zaft zaft(a)azstarnet.com

22 years, 3 months

WTD: Microvitec "CUB" 653 service/user manuals

by philpem＠dsl.pipex.com

Hi, I'm trying to track down a Service Manual and a User's Manual for my Microvitec Cub 653 RGB monitor. Has anyone here got copies of these manuals? I'd be willing to pay for photocopying, though it would be easier for me if you could just put the manuals in a scanner and send me the resulting image files. I have access to an FTP site I could use for this purpose. Thanks. -- Phil. philpem(a)dsl.pipex.com http://www.philpem.dsl.pipex.com/ PGP Key ID: 0x0E18C95F PGP Key Fingerprint: 2741 5CB7 1D45 6F77 D1FC FA3D 7A87 2DA4 0E18 C95F

22 years, 3 months

EIA 232 vs. 422, Color Computers (was Re: Serial floppy drives)

by dwightk.elvey＠amd.com

>From: "Fred Cisin (XenoSoft)" <cisin(a)xenosoft.com> > >> > similar. 422 by the way is specified to go almost 1000 feet, while with 232 >> > you are lucky to get over 10 feet. Regards - Mike > >On Thu, 5 Sep 2002, Sellam Ismail wrote: >> That's not true. Serial cable can go for a good many feet before the >> signal breaks down (someone should pipe in with actual data ;) > >It'll handle way more than its spec calls for. When researching the >content for "RS232 Solution", Joe Campbell ran it through a couple of >thousand feet of wire (on a spool). Well, I guess that by being on a >spool, the two ends were less than 10 feet apart. :-) > > >The original IBM PC Parallel Printer Port was the one that was spec'ed at >10 feet (3 meters). I often ran 30 feet with it. >I have no idea what the spec is for 1284. > > Hi Fred Did he stretch the spools out and put a 5 PH blower that cycles on and off in each machine at the ends. I think not! There is a big difference between running a signal through a spool ( effective length for noise being vary short ) and running in a low noise environment as compared to many real world environments. In the spool, he was only looking at resistive loss and not any of the other factors. On your PC example, it was intended to run in a low noise environment. If it failed to work, IBM would simple shrug and say 'You are only suppose to run it with a nice PC and nothing else. It was never intended to be used like that.' Besides, the parallel port is suppose to be a terminated signal and not subject to issues of under driven, as in the case of RS-232. Dwight

22 years, 3 months

EIA 232 vs. 422, Color Computers (was Re: Serial floppy drives)

by dwightk.elvey＠amd.com

Hi 422 can be an impedance controlled line with terminations. 232 tends to be under driven on typical lines and unterminated. This means that an 232 signal will look like a stair case to the receiver input that on long runs may cause intermittent edges. At lower baud rates, most 232 receivers can handle this much distortion. Also, since it is under driven, the signal can be corrupted by even a small amount of outside noise. This is made even worse because it is single ended and any common mode noise can corrupt the signal. In other words, just because you ran it in your house for 30 feet and never saw an error doesn't mean it can be done in all cases. 422 is impedance controlled and can be used at baud rates up to 5 or 10 MHz ( depending on manufacturer ). It can do this until resistive losses bring the level too low to be detected. Being differential, only common mode noise that pushed it beyond the common mode will be an issue and if the noise is short term, the receivers are designed to not switch the outputs until they are brought back into the common mode. I once designed a communications bus using RS-485 ( similar to RS-422 ) lines to interconnect several machines in a noisy environment. The previous design used RS-232 and was not robust enough to work in that same environment. The lines were less than 15 feet on the RS-232. The RS-485 setup ran for over 10 years without logging a single bit of data loss ( there were several component failures during that time that don't count ). Dwight >From: "Mike Feher" <n4fs(a)monmouth.com> > > >OK, I may be wrong, ( will not be the first time) I do have the original >Mil-STD or EIA specification on these interfaces, and admit that it is not >my specialty, however, it is fact, to the best of my recollection, that 422 >will be reliable over a lot more distance than RS-232. I will dig out the >document, when I get a chance and quote actual specified numbers. Regards - >Mike > > > >Mike B. Feher, N4FS >89 Arnold Blvd. >Howell NJ, 07731 >(732) 901-9193 > > >----- Original Message ----- >From: "Sellam Ismail" <foo(a)siconic.com> >To: <cctalk(a)classiccmp.org> >Sent: Thursday, September 05, 2002 9:24 AM >Subject: Re: EIA 232 vs. 422, Color Computers (was Re: Serial floppy drives) > > >> On Thu, 5 Sep 2002, Mike Feher wrote: >> >> > similar. 422 by the way is specified to go almost 1000 feet, while with >232 >> > you are lucky to get over 10 feet. Regards - Mike >> >> That's not true. Serial cable can go for a good many feet before the >> signal breaks down (someone should pipe in with actual data ;) >> >> Sellam Ismail Vintage Computer >Festival >> -------------------------------------------------------------------------- >---- >> International Man of Intrigue and Danger >http://www.vintage.org >> >> * Old computing resources for business and academia at >www.VintageTech.com * >> >> > >

22 years, 3 months

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test-drb September 2002