test-drb

test-drb@ccmp.vtda.org

101090 discussions

by pdp11＠saccade.com

One thing I've always been really curious about is who invented the seven segment display. Not a particular implementation of it, but the graphic design concept that seven bars are all you need to display the digits 0 - 9. I'd always assumed it was something that originated from the creation of electronic calculators. The first Friden EC-130 for example, uses seven segment patterns on a CRT (machines prior to that used Nixie tubes). Well, leave it to Don Knuth to dig up a much older reference. While browsing his web pages, I noticed a reference to patent 974,943 by F.W. Wood, issued in 1910(!). It describes an electro-mechanical "Illuminated Announcement and Display Signal" with a segmented display. Wood actually uses eight segments (so his "4" has a slanted top), but other than that, it's exactly the same design as the digits today's cheap watches and calculators. Patent (you may need to register first): http://www.freepatentsonline.com/0974943.pdf Cheers, jp

18 years, 8 months

IBM 4865 (External 3.5" floppy) power pigtail connector

by mbbrutman-cctalk＠brutman.com

I've acquired an IBM 4865 drive for my 5160 XT - it is a 3.5" external drive. I've got the 1.44MB version which is wrong for the XT, but with the correct media (1MB diskettes) it might work. Besides the normal 37 pin D shell connector that goes to the back of the floppy controller this drive has a little 4 connector pigtail to provide operating voltage for the drive. I've picked the drive apart and I think I know what the pins on the power pigtail are supposed to be. I'd like to find a nice matching socket for the pigtail instead of just hacking it, but after an hour into the world of Molex and Amphenol I've decided to ask for help ... The picture can be found here: http://brutman.com/dscf6030.jpg Thanks in advance, Mike

18 years, 8 months

Cromemco & Persci drives (was PS/2 interface &c)

by dm561＠torfree.net

Date: Tue, 18 Sep 2007 22:56:31 -0400 From: "Roy J. Tellason" <rtellason at verizon.net> Subject: Re: Cromemco & Persci drives (was PS/2 interface &c) <snip> >> it's sometimes convenient to hook up a known good 5 1/4 drive to check out >> the rest of the system and get it up & running before you dig into the 8". >> Also makes it easier to make disks from PC images if you need them. >It's been a really long time since I played with it, but I remember the rest >of the system working okay, more or less. There's a CPU board and a 64K RAM >board in there, besides the FDC (which if I'm remembering right also has the >printer port on it). Does 16FDC sound right? 16FDC sounds right but this takes us back to the original topic: that DB-25 is the RS-232 console port, not a printer. >> If there's no HD you might have trouble finding 12V though & need a >> separate supply or regulator; an external powered 5 1/4 disk in a nice >> enclosure is a useful peripheral for a System3. >I suppose I could rig one up, but I don't know about hacking together a BIOS >for that machine. I never did get into that stuff all that much. Well, you wouldn't have to hack the BIOS but (assuming you're running CDOS) you'd need a 5 1/4 CDOS image; I think Dave D has some on his site. Good luck. mike

18 years, 8 months

Apple IIc+ boot disk for DOS3.3

by HGoff＠2-10.com

Do you stock this diskette?

18 years, 8 months

did anyone else go to MIT?

by chrism3667＠yahoo.com

that show is not what it used to be. Certainly not worth the ~300 mile drive. It used to be in a different location and was at probably 2x as big. Did talk w/some interesting people. I met a guy who has 3,000 computers, including some VERY big iron. Can you say you know anyone w/this many puters? Can you? I think not. MUAHAHAHAHAHAHA ____________________________________________________________________________________ Be a better Heartthrob. Get better relationship answers from someone who knows. Yahoo! Answers - Check it out. http://answers.yahoo.com/dir/?link=list&sid=396545433

18 years, 8 months

EPROM Erasers?

by trag＠io.com

>Date: Sun, 16 Sep 2007 06:57:40 -0700 >From: dwight elvey <dkelvey at hotmail.com> > A carbon arc would work as well but I've not seen these >since they've stopped using these in search lights. >Dwight Back in elementary school one of the library books had interesting projects in it. One project was to remove the carbon rods from four 'D' cells. They're about 1/4" - 3/8" in diameter and run the length of the cell. It's a bit of a trick to extract them without breaking them. Once you have four carbon rods, suspend two in a jar of salt water. Grip the other two, each with its own wooden clothes pin (the spring type, not the slot type). Now steal a heavy duty electrical cord from something like Mommy's clothes iron. Attach one lead of the cord to one of the carbon rods in the jar of salt water. Connect the other lead to one of the carbon rods held by a clothes pin. Now use a spare length of heavy wire to connect the remaining two carbon rods together. Plug the cord into the wall. Now carefully touch the tips of the two clothes pin carbon rods together and then slowly draw them apart. TADA! Carbon arc. Vary the salt content in the jar to adjust the power. I don't recall the instructions saying anything about not looking directly at the arc. Perhaps this method doesn't generate enough UV to be useful/harmful? I spent a fair bit of time staring at the thing. Thirty-five years later I haven't noticed any vision impairment, but maybe I was young enough for my retina to recover. It was quite the attention getter at the ES science fair. I suspect books in grade schools don't contain cool/dangerous projects like this any more. I only electrocuted myself once or twice by touching the live bits of the contraption... Jeff Walther

18 years, 8 months

Repro Cromemco joysticks...

by wh.sudbrink＠verizon.net

Hi All, I want to build a couple of reproduction (work alike) Cromemco joystick consoles for two reasons: 1) I don't have any real ones. 2) I'll be able to let the "unwashed masses" (my children included) play various games with worrying about them getting destroyed. To this end, I've looked at the pdf of the manual and (to my delight) discovered that I have all of the required parts. Well, almost. Two things: 1) The manual calls for a 45 Ohm QUAM speaker. All I have are plain old run-of-the-mill 8 Ohm internal PC speakers. My ignorance of basic electronics shines through... 30 minutes of googling and I'm not sure what QUAM means. Anyway, can I substitute the speaker? With some modification to the schematic? 2) The manual does not specify the pot values on the joystick. The joysticks I have have 100K Ohm pots (thanks Tim Shoppa!). Is that value correct? Is the value important? Can I adjust for it on the D+7A or in the circuit on the joystick side? Also, an esthetic question: are the joysticks on the original self-centering? Thanks for any help! BTW: Both manuals (joystick console and D+7A card) are in the Harte repository. No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.487 / Virus Database: 269.13.22/1013 - Release Date: 9/17/2007 1:29 PM

18 years, 8 months

Calcomp 1043GT plotter in Salem, OR

by cclist＠sydex.com

Just saw this one on Craigslist: http://eugene.craigslist.org/sys/425978406.html Cheers, Chuck

18 years, 8 months

EPROM Erasers?

by dkelvey＠hotmail.com

> From: arcarlini at iee.org> > Jeff Walther wrote:> [snip description of carbon arc, mains power and hand-held clothes pegs> :-)]> > > I don't recall the instructions saying anything about not looking> > directly at the arc. Perhaps this method doesn't generate enough> > UV to be useful/harmful?> > Perhaps the odds of surviving long enough for UV exposure to be an issue> turned out to be quite low :-) At least over here in the 240Vac world.> > Antonio> Hi I see people talking about looking into a UV light source. If you are worried about the internals of your eye, don't worry. The cornea will absorb the UV for you. Then, you may need cornea surgery to replace your damaged cornea. It doesn't matter if you are looking directly into a UV light source, it is just if there is a direct line between your eye and the UV source. People don't understand microwave ovens either. It isn't looking into the microwave that is the problem, it is getting your eyes close to a leaky microwave seal. You can look into a microwave oven as much as you like as long as you don't get too close. With microwaves it is the inside of the eye that is damaged. As was pointed out, the instructions didn't mention electrical shock either. As I stated before, it is the temperature that creates the UV. If it looks blue-white, it is most likely producing UV as well. If it is yellow or orange, it is most likely not. Also remember that little UV is reflected from surfaces. Dwight _________________________________________________________________ Gear up for Halo? 3 with free downloads and an exclusive offer. It?s our way of saying thanks for using Windows Live?. http://gethalo3gear.com?ocid=SeptemberWLHalo3_WLHMTxt_2

18 years, 8 months

Handheld VAX and System/370.

by andy＠smokebelch.org

OK I realise this is cheating slightly but I still thought it was quite cool that it worked... SimH on a Nokia N800: http://carrierdetect.com/?p=39 VM/370 R6 under Hercules on an N800: http://carrierdetect.com/?p=40 Just wish the thing had a CF slot and thus could take a Microdrive, in order that I wouldn't have to worry about frequent writes to flash storage. Speaking of which does anyone know if VMS can live without page and swap files? Somehow it doesn't seem likely... Trying to work out how I could make it do as little writes as possible to the FS, e.g. by disabling opcom, auditing and so on. And is there a 'noatime' mount option equivalent for ODS? Andrew ---------------- Andrew Back a at smokebelch.org

18 years, 8 months

cctalk Digest, Vol 49, Issue 50

by wdg3rd＠comcast.net

This message has been processed by Symantec's AntiVirus Technology. Unknown00000000.data was not scanned for viruses because too many nested levels of files were found. For more information on antivirus tips and technology, visit http://ses.symantec.com/

18 years, 8 months

Cromemco & Persci drives (was PS/2 interface &c)

by dm561＠torfree.net

-----------------Original Message: Date: Mon, 17 Sep 2007 19:50:25 -0400 From: "Roy J. Tellason" <rtellason at verizon.net> Subject: Re: PS/2 Interface (was: Wang 300 Calc] On Monday 17 September 2007 18:57, Tony Duell wrote: <snip> > I have an S100 amchine called a CASU Super C. It contains a Cromemco CPU > board, some other stnadard 64K RAM bvoard, a Micromation Doubler disk > controller and CASU-designed boot ROM and seiral interface boards. > > The disk drive (a Persci) is in a separate box. The 50 wire interface > cable is split down the middle adn connected to a pair of DB25s... I have a Cromemco "System 3" (?). It also has a Persci drive in it, a dual. Is that what yours is? There's apparently some sort of a problem with mine, as the floppy which was in it when I got it had been tried so much and for so long that the initial tracks were completely worn away, and you could see through it. On perusing the service data for it, I notice that the drive uses a bunch of _incandescent_ light bulbs for things like index sensor, etc. I would imagine that one or more of these is likely to be the problem. I'd deferred working on it because you can't do much with it in the computer case, and I needed to make some sort of extension for the power cable to the drive, which was a rather odd connector... Nice machine, in that the S-100 card cage pulls out like a drawer. Too bad it's not working. ------------Reply: Lots of luck with that Persci; nice and fast when they worked, but... My 3s all have Tandon singles; slower but infinitely more reliable. You probably know, but the controller can use both 5 1/4 and 8" drives; it's sometimes convenient to hook up a known good 5 1/4 drive to check out the rest of the system and get it up & running before you dig into the 8". Also makes it easier to make disks from PC images if you need them. If there's no HD you might have trouble finding 12V though & need a separate supply or regulator; an external powered 5 1/4 disk in a nice enclosure is a useful peripheral for a System3. Relevant to the original discussion: Cromemco's external 5 1/4 FDDs and tape drives used a standard Amphenol IEEE connector as used on parallel Commmodore FDDs &c (not IEEE protocol though ;) mike

18 years, 8 months

Magazines on ebay

by silent700＠gmail.com

For those who collect old Byte and Interface Age mags, I've begun posting my duplicate issues on the 'bay. If you're interested, here's the link to my listings: http://search.ebay.com/_W0QQsassZdev*null -- jht

18 years, 8 months

Help identifying a keyboard?

by sethm＠loomcom.com

Hi folks, Can anyone help identify the keyboard in these photos? (apart from the obvious, that it's made by Stackpole and has a part number of 86-90-0048 ;) http://www.loomcom.com/junk/stackpole1.jpg http://www.loomcom.com/junk/stackpole2.jpg I picked it up for fifty cents at a swap meet in the hopes that it might be an ASCII keyboard that I could use in an Apple I replica, but given that it has a 40-pin DIP socket, it's clearly not (it was very early in the morning, what can I say). It has a five-pin power header on the top left, two red LED indicators, the aforementioned 40- pin DIP socket, and only one IC, an SN7414N, so it's obviously not doing much logic. -Seth

18 years, 8 months

Ancient 8086/80286 unixes?

by RodSmallwood＠mail.ediconsulting.co.uk

Surely any publisher of an article past or present and where software is an important part of the design and who does not print a listing is only doing half the job. If they are doing this to sell a few preprogrammed chips then shame on them. For old designs we may come across and wish to restore and are prevented by this practice lets have a 'Wall of Shame' to identify those people who left us a legacy like that. Rod Smallwood -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Tony Duell Sent: 14 September 2007 20:41 To: cctalk at classiccmp.org Subject: Re: Ancient 8086/80286 unixes? > > On Thursday 13 September 2007 01:30:39 Ensor wrote: > > > I first came across this myself in the mid-90s. I'd picked up a copy > > of "Elektor" for the first time in almost 10 years and was surprised > > that they didn't provide any listings of any form for the projects > > based around PICs, you had to send away for pre-programmed parts. > > That's about when I remember seeing it happen; also with an article in > (possibly) PE&EE about building a Z80-based SBC that ran Forth. Actually, Elektor have been rather better about this recently, and in a lot of cases the _source_ code for the microcontroller firmware is available as a free download from their web site. Alas, in some cases (often for the projects I am most interested in :-(), this is not the case, often becasue the author gets a royalty from each pre-programmed chip sold. > > These days when you can build a simple PIC or ATMEL programmer from a > couple of components, or buy an EPROM programmer off eBay for about a > tenner, there's not really an excuse. I suspect the reason (not an excuse...) was that they made money selling pre-programmed chips. Certainly when you boughht the pre-programmed chip, it came copy-protected. > > Ob. on-topic: does anyone remember the Forth SBC article I was talking > about, and does a copy of it exist online anywhere? No, and as a Forth (and stack based languages in general) lover, I would be interested. -tony

18 years, 8 months

did anyone else go to MIT?

by dkelvey＠hotmail.com

> To: cctalk at classiccmp.org---snip--- > > > > My collection's size isn't primarily due to the number of machines, but > > instead because of the size of my machines. And there are a few people > > on this list whose collections are the size of mine or larger, at least > > that I know of.> > > > Hmmm.. A new way to define ones collection - by the space it takes up! :)> Hi I have a 20 foot container with shelves and a small walk space. about 15 percent is old radios. The reset is computer related. I'd estimate that about 75% of my computer collection is inside the container. As I recall, the container is 8X8X20. I have stiff to the ceiling as well as some across the top of the walk way such that one has to duck in places. One can do the math. Not as big as many but still a nice collection. Dwight _________________________________________________________________ Kick back and relax with hot games and cool activities at the Messenger Caf?. http://www.cafemessenger.com?ocid=TXT_TAGLM_SeptWLtagline

18 years, 8 months

New acquisition

by RodSmallwood＠mail.ediconsulting.co.uk

The Dec20 is good but get a load of that DS570. Now that is really nice Rod -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Zane H. Healy Sent: 18 September 2007 05:00 To: General Discussion: On-Topic and Off-Topic Posts; General at shiresoft.com Subject: Re: New acquisition At 8:47 PM -0700 9/17/07, Guy Sotomayor wrote: >Hi, > >I just wanted to let y'all know that I recently acquired a DEC 2065. >I put up a quick web page of how my shop is being reorganized to >accommodate the new "toy". Warning this is not a permanent location >(ie if you link to it you may not find it in a month). > >http://web.mac.com/ggs17/site Drop the site from the URL and it will work... http://web.mac.com/ggs17 I'm not sure, if I'm jealous, or relieved that I'm not the one trying to take care of that BEAUTIFUL system! What are you going to run on it? What were you running on the KL10? Zane -- | Zane H. Healy | UNIX Systems Administrator | | healyzh at aracnet.com (primary) | OpenVMS Enthusiast | | MONK::HEALYZH (DECnet) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | PDP-10 Emulation and Zane's Computer Museum. | | http://www.aracnet.com/~healyzh/ |

18 years, 8 months

Handheld VAX and System/370.

by ajp166＠bellatlantic.net

> >Subject: Re: Handheld VAX and System/370. > From: Andrew Back <andy at smokebelch.org> > Date: Tue, 18 Sep 2007 08:23:06 +0100 (BST) > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On Mon, 17 Sep 2007, Sridhar Ayengar wrote: > ><<SNIP>> > >>> Just wish the thing had a CF slot and thus could take a Microdrive, in >>> order that I wouldn't have to worry about frequent writes to flash storage. >>> Speaking of which does anyone know if VMS can live without page and swap >>> files? Somehow it doesn't seem likely... Trying to work out how I could >>> make it do as little writes as possible to the FS, e.g. by disabling opcom, >>> auditing and so on. And is there a 'noatime' mount option equivalent for >>> ODS? VMS cannot live without page and swap. What you can do is maximize the memory it has to reduces the need to psge/swap. >> Wasn't there someone making an outboard adapter for SD that holds a CF? I >> have something similar that holds a CF and plugs into a SmartMedia slot. can't help on that. Allison

18 years, 8 months

Help identifying a PDP-11

by RodSmallwood＠mail.ediconsulting.co.uk

Look further down the list for a post entitled "Re: New acquisition" This guy has the the most boo-ti-ful DS570 Decdatasystem I have ever seen. All the right periperials, LA36 console priner, VT crt and what looks like an LP11 line printer. Get a load of that lights and switches front panel. I think the DS570 is the 11/70 version. Rod -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Rod Smallwood Sent: 17 September 2007 17:39 To: General Discussion: On-Topic Posts Only Subject: RE: Help identifying a PDP-11 A couple of other things have come to mind. DEC DataSystem usually indicated that it supported *DIBOL running under OS/8, RT11 or VMS They were intended to be a business package system ready run and often included training, installation and maintenance. There's a possible confusion here 'DEC System' refered to a DEC10 or DEC20 and DEC DataSystem to one of these package jobs. *Program Structure like COBOL. Syntax like Fortran/BASIC. BCD Arithmetic Rod Smallwood -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Tim Shoppa Sent: 17 September 2007 13:50 To: cctalk at classiccmp.org Subject: Re: Help identifying a PDP-11 > Can anyone help me identify my latest PDP-11 rescue. Not been able to > get a good look at it yet as it is in a room packed (and I mean > packed) with junk. Machine consists of a DEC Datasystems cab (about > 35-40U with a blue bottom panel, pretty similar to light blue cabs here: > http://www.computermuseum.li/Liste/Digital/PDP11.70.4.html) > I'm not familiar with the DEC Datasystems versions of PDP-11s. Does > anyone have any background information on them? > Also, I'm pretty sure I've not lucked out and found an 11/70 as no > toggle switch console, any ideas on what other models were fitted to > these cabs. I'm guessing 11/34. That is an 11/70, but with the "remote diagnostics console". You will find a M8255 KY11-RE in there to connect up a modem to give remote console access. Probably hooked up to a modem that was owned by DEC maintenance org and leased as part of the maintenance agreement. I'm sure that sometimes they asked for the modem and console back if the maintenance contract was terminated but as a practical matter I find that they hardly ever reclaimed the equipment. Tim.

18 years, 8 months

New acquisition

by ggs＠shiresoft.com

Hi, I just wanted to let y'all know that I recently acquired a DEC 2065. I put up a quick web page of how my shop is being reorganized to accommodate the new "toy". Warning this is not a permanent location (ie if you link to it you may not find it in a month). http://web.mac.com/ggs17/site -- TTFN - Guy

18 years, 8 months

cctalk Digest, Vol 49, Issue 51

by dm561＠torfree.net

----------------Original message: Date: Mon, 17 Sep 2007 23:57:59 +0100 (BST) From: ard at p850ug1.demon.co.uk (Tony Duell) Subject: Re: PS/2 Interface (was: Wang 300 Calc] >> When I think about it, the MITS 8800 had connector punchouts for DB25 >> *only* in the back panel. DB25 seemed to be the lingua franca back >> then for hobbyist interfaces. If one had an 8" floppy drive, one ran >> the ribbon cable right through the crack between the back panel and >> the case cover directly to the controller card(s). No DD50s. >I have an S100 amchine called a CASU Super C. It contains a Cromemco CPU >board, some other stnadard 64K RAM bvoard, a Micromation Doubler disk >controller and CASU-designed boot ROM and seiral interface boards. >The disk drive (a Persci) is in a separate box. The 50 wire interface >cable is split down the middle adn connected to a pair of DB25s... >-tony ---------------Reply: Cromemco did the same thing with their external 8" IMI hard disks; the Z-2 could have one internal (sacrificing half the slots to make room) but if you wanted more you got a 2-drive HDD cabinet the same size as the Z-2 connected through 2 DB25s. mike

18 years, 8 months

[SPAM(date)] Tore's website

by toresbe＠ifi.uio.no

http://gunkies.org/stuff/CV.html

18 years, 8 months

Catweasel Mk1-3 not suitable for archiving - why?

by lynchaj＠yahoo.com

Hi, I've been doing some more work on the FDD reader/writer, and I came across an interesting note on the Software Preservation Society website: > We cannot yet support the Catweasel for technical reasons, primarily because > it does not yet enable us to read disks in sufficient detail for dumping, nor > does it allow writing IPF files back to disk. And while it does seem that the > Mk4 would be suited to the job, current models are still running Mk3 firmware > and drivers, meaning that we are still no closer forward in this regard. > > As soon as Mk4 firmware is available for these cards, we will do our best to > obtain one with a view to support it for these purposes. Until then, our hands > are tied. [http://www.softpres.org/glossary:catweasel] Now what I'd like to know is, what part of the Catweasel's design prevents it >from being used for archiving discs? From what I remember, the Amiga FDD controller is a bog-standard raw reader with an MFM sync detector. All it does is sync up to a bitstream and read it >from the disc as a raw stream until it gets told to A) shut up or B) receives another MFM sync. From what I've read, the Catweasel differs only in that it measures the timing between bits, and can do MFM pre-decoding. So what part of its design makes it such a bad choice for this kind of work? FWIW, I'm almost at the point where I can start thinking about doing the PCB designs for the USB floppy disc reader/writer. I've found a solution to the lack of I/Os on the microcontroller (which involves adding a second CPLD to act as an bus expander - probably over I2C). I'm going to do some testing on the bus expander Verilog code tonight, and update the schematics, then any spare time I get next week will probably be spent working on the PCB artwork. My intention is to take a weekend off work at some point in the next month to build up the prototype and do some coding and testing. If all goes well, I might do a small production run in November, depending on interest. -- Phil. | (\_/) This is Bunny. Copy and paste Bunny classiccmp at philpem.me.uk | (='.'=) into your signature to help him gain http://www.philpem.me.uk/ | (")_(") world domination. Phil, I have seen the SPS website you mentioned and read this thread but for the life of me I cannot understand why the Catweasel would be unsuitable for archiving vintage computer floppy disks. If fact, I think a Catweasels raw "bit dump" would be the idea archiving format since it records all the details found on the track. Maybe wrap the raw data in a container format with metadata like the DMK. With Catweasel, you can see everything on the track clock, data, junk, etc. Whatever is there you can see it in the raw data. Once you have the raw bit dump you could make near identical copies or write programs to extract the data files, work with emulators, etc. Regardless of the SPS position, I know some people are already using the Catweasel for archiving vintage computers. Tim Mann's software pretty much covers the almost the whole soft sector disk format spectrum and Jim Battle made a SOL-20/PTDOS hard sector disk imaging program. I think someone else made a program to archive Data General disks. Catweasel seems like the way to go to me. If there is something else out there as good, especially for the hard sector disks, I would certainly like to hear about it. Has anyone tried Disk2FDI on any hard sector formats? It sounds interesting and inexpensive if it works. Thanks! Andrew Lynch

18 years, 8 months

cctalk Digest, Vol 49, Issue 46, Message 18, PS/2 Interface (was: Wang 300 Calc]

by mike＠brickfieldspark.org

Try www.bulgin.co.uk and go for the General Connectors page (http://www.bulgin.co.uk/Products/GenPurpose_Connectors/GenPurpose_Connector…) Many type on that page but I think you should see what is described towards the bottm. Mike. > Anyway, the connectors I am thinking of were part of as series. They were > circular, most of them were chassis mouting plugs and cable sockets. The > plug was recessed into the panel, and the socket part fitted into it. > There were 1.5A and 5A versions with 2, 3, or 6 pins. Polaraision was > acheaived by a groove down the side of the socket part and a > corresponding ridge in the recessed plug. In many cases the wire > terminals on the socket part were covered by a simple screw-on cap which > means they're not not approved for use above 50V (since you can unscrew > said cap and get access to live parts without the use of a tool). There > were later mocels of some of the sockets with the cover held on by > screws, AFAIK those are still OK for mains use. > > If you like I can tey to find the part numbers for them. > > -tony > >

18 years, 8 months

PS/2 Interface (was: Wang 300 Calc]

by dm561＠torfree.net

--------------Original Message: Date: Fri, 14 Sep 2007 21:09:17 +0100 (BST) From: ard at p850ug1.demon.co.uk (Tony Duell) Subject: Re: Wang 300 Calc > > On 13/09/2007, Gordon JC Pearce <gordonjcp at gjcp.net> wrote: > > > It still doesn't excuse having a physically-but-not-functionally > > interchangeable connector for PS/2 mice and keyboards, though. That is > > where USB has a big win. > > Absolutely 100% concur. That was criminally stupid. IIRC, the PS/2 mouse interface and PS/2 keyboard interface are very similar. Both are TTL level interfaces with clock and data lines, both have 4 signals on the connector (+5V, ground, clock, data), and the data transfer protocol is much the same. IIRC, the pin assignemts of the 2 interfaces is the same too, and it's possible to make a device where you can plug the mouse and keyboard into either connector, and detect what sort of device is plugged into a given socket. The fact that most PCs didn't let you do that is not the fault of the interface. So why not use the same connector for the 2 interfaces? -tony -----------------Reply: Why not indeed; old Compaq laptops have a single connector which will accept either a mouse or an external keyboard (an external key_pad_ used a submini earphone-type connector). IBM allowed for both together; a mouse or external keypad connected directly to the single connector while an external keyboard required a Y adapter which routed the keyboard clock & data signals to the two unused pins. And then there are the dual-mode mice which put RS-232 on the unused pins and came with an adapter so they could be used either way... Laptops were probably also a reason for reducing the size of the connector. "Criminally stupid"? I suppose you'd also want incompatible connectors for the right & left channels of your stereo? ;-) Funny how on the one hand I read the sentiment here that people should be required to pass a course in advanced computer science before being allowed to plug in a computer, and then that they should be so simple to hook up that a retarded^H^H^H^H mentally-challenged blind^H^H^H vision-impaired chimpanzee could do it; just no pleasing some folks... m

18 years, 8 months

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