test-drb

test-drb@ccmp.vtda.org

101090 discussions

by pat＠computer-refuge.org

A new mainframe. :) http://computer-refuge.org/compcollect/ibm/s390/mp2003/ Happy holidays to all! Pat -- Purdue University ITAP/RCAC --- http://www.rcac.purdue.edu/ The Computer Refuge --- http://computer-refuge.org

19 years, 5 months

Remex PT board unibus or q-bus?

by richardlynch3＠comcast.net

Does anyone know if the Remex paper tape reader/punch interface board for PDP-11 marked "109831" is unibus or q-bus? Is it generic enough to work in any PDP-11 with that bus? Thanks, Richard Lynch

19 years, 5 months

Weird disk drive

by chrism3667＠yahoo.com

a picture would be nice. Can the enclosure accept 2 drives? If so do they sit vertically? Whats the model # of the drive itself? __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

19 years, 5 months

multiple CGA cards on ISA bus?

by chrism3667＠yahoo.com

its too painful at times :%. But the question comes up what software is intended to run on this amalgamation...off the shelf or custom... __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

19 years, 5 months

multiple CGA cards on ISA bus?

by chrism3667＠yahoo.com

19 years, 5 months

multiple cga cards

by chrism3667＠yahoo.com

the Peanut used some sort of gate array to make the vid memory appear as it were in cga space to the warez, but was actually deep down low IIRC. If that helps.. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

19 years, 5 months

Cylinders versus tracks...

by blstuart＠bellsouth.net

> Oh, that's another thing - is there a correct convention for track numbering? > There seem to be equal numbers of apps out there which treat the first track > as track zero as there are which treat it as track one :-) (Personal > preference would be to number from zero, just because it likely makes some > programming calculations easier, but I'm not sure if it's technically wrong to > present that visually to the user...) I'm not sure there is a correct convention. I do know that controller programming can be a bit weird. The old AT-style controllers on PCs seemed to want the cylinders and heads numbered from 0 and the sectors numbered from 1. I don't have any hardware docs with me at the moment, but that's what I've seen in drivers. As an aside, it's fun to try to explain to a class who've only seen sanitized classroom examples that the real world is filled with stuff like this. That's why I like to teach OS with code, and not just general principles. BLS

19 years, 5 months

Advice for tape drive repair / maintenance

by Billy.Pettit＠wdc.com

Tony Duell wrote: I can't comment on whether it's possible to make reliable, long-lasting, devices with lead-free solder (although there seem to be exemptions for what I'd call 'critical' applications (military, aerospace, medical, etc) in the UK regulations which allow the use of leaded solder for such devices, so draw you own conclusions). ---------------- I've put a call into a specialist friend who does mil-spec here. Last time I talked to him he said they couldn't use lead based. In fact most of his "hardened" designs had to be laser welded. But I want to verify what US mil-spec calls for currently. ------------------- But I can assure you I've had enough dry joints in modern stuff assembled with lead free solder to last me a lifetime. I've even had brand-new stuff that's had to be resoldered before it will work. And I've met plenty of other repairers (entusiasts and professionals) who have had the same problems. > producer of PCBs has had more than 5 years to move to lead free = > environment. > That was not a difficult change for competent manufacturing engineers to > make. > > Yet, I think this is the third or fourth time you've brought this up. = > You > must have had a bad experience someplace and are judging the technology = Not 'a' bad expeience, but many of them. > by > that experience. I know a lot of hobbyists, as well as lab technicians, = > were > annoyed at having to buy new soldering equipment for higher temperature > boards. I can't see what a hobbyist would have to bother -- at least in the UK, these directives only apply to equipment that's offered for sale. You cna do what yuou like in stuff you build for yourself. ---------------- Like you, many hobbists want to repair or modify equipment they buy. And even more simple users like myself, where I buy PCBs and salvage the parts I want. For example, I found some boards with 10 nanosecond 32Kx8 RAMS that were perfect for a logic analyzer I want to build. A bitch to get off, even though surface mount. Wish they were some of those bad joints you see - these almost had to be cut off. ------------------- > > But the world has moved on. Lead free soldering is as good and in many > cases better than lead based soldering. On the data from more than 100 > million lead free PCBs, I can attest dry solder joints are not a = > problem. > > As for the cheapest plastic imaginable, I just don't see that in the > marketplace. My current assignment is working with DVRs, STBs and TVs = Perhaps your consumer electronic devices are built a lot better than ours. THis all started with a mention of a $89 VCR. Over here that's a '50 quid VCR' and yes, we get them at that sort of price. Now, when I last bought a VCR, some 15 years ago, it cost nearly \pounds 1000 (or 20 times as much). Are you seriously telling me that, even though there's been inflation in that time, a modern 50 quid machine is going to be as well made anf as long lasting. Becasue I simply don't see that. > using > disk drives. So I always have a couple of dozen units torn down on my > bench. What I see are vendors that have had 20+ years to refine their > design, their processes and their materials. I see components and = > systems > that have an order (or orders) of magnitude better reliability than the > products of 20 years ago. I think the big change is that 20 years ago there was good stuff and bad stuff out there. I mentioned I'd paid \pounds 1000 or so for a VCR. There were much cheaper machines around at the time, sure, and they probably have not lasted 15 years. But if you wanted to spend the money you could get one that lasted, that was maintainable (the manufacturers not only produced an excellent servive manual, but they sent it to me free of charge when I asked about it), etc. Now I see \pounds 50 VCRs and \pounds 20 DVD players and nothing else. I'd love to be able to spend more money and get a better machine, but I can't. > > This "everything old is good, everything new is crap" is not verified by = > the > data from the industry world wide. Some things do improve with time. > Especially in a cut throat competitive industry where warranty costs = > from > poor products will put you out of business in weeks. Customers (and in = > the > US, laws) demand reliable products. Companies don't survive if they = Not over here they don't. People upgrade because a new model is available with more features (they they probably will never use). Provided the machine lasts for the warranty period the manufacturer is happy. If it fails after that time he gets to sell another one. ------------------------------------ This is one area I will agree with you. My experience at Philips exposed me to the enormous difference in consumer protection laws in the US versus the rest of the world. Philips management had a terrible time dealing with these differences. For example, if a box is even opened here, the unit automatically becomes "used" and has to be marked as such. (Usually referred to as white labelling.) Customers can return a product without giving any reason. It doesn't have to be a failure. Cosmetic damage consititutes a failure. This includes the packaging. Another huge difference is that refurbished units have to be sold as used, even if they have a new product warranty. (Philip's answer was to sell the reburished units through the employee stores.) This is also true if the unit was refurbished before it ever left the factory. Of course that rule is ignored by everybody. But big accounts like Apple and Dell still insist that no unit can be reworked. They demand only prime yield product. All of these laws were different from the typical consumer protection laws in Europe. There, many manufacturers used a 5% rule. 5% of what they ship is defective. They give the distributors extra units as a margin against returns. Sadly, many of the returns are sold as new. There are no laws in the Common Market to prevent this. Management used to this Euro environment had a terrible time adjusting to the US conditions. Some couldn't even understand the concept of a rebate: if you advertised a rebate, you have to pay it! That lesson cost several European companies tens of millions of dollars and government law suits to learn. One result of these differences is that European companies normally don't normally thrive in the US. The cultural gap in business is too great. When I went to work for Philips, no one I knew here was aware Philips made anything besides light bulbs. It is not a well known brand name here, like Sony and Panasonic. So I can accept that you see a much lower level of quality than is normal here in the US. We still see some crap, but we can do something about it. --------------------------- > Tony, you have your preferences and choices and more power to you. But = > if > you did a study of current state of the art electronics, you would find = > it > to be far superior to that of 20 years ago. Even if it won't provide a > maintenance manual. Sorry, I have looked at modern stuff and found that in many cases the performance and quality of construction is markedly inferior to that which I already own. Perhaps you could explain to me in what ways I am going to find it 'superior'. -tony --------------------- Tony, your heart and mind are in the past. No matter how many facts, figures, statistics I present, I will never convince you that today's world is as good as your golden age when everything was perfect. Why bother? It's just unpleasant for both of us. I've spent 46 years in the electronics industry, always on the cutting edge, and always striving for improvement. I see enormous changes, most for the good. You don't. I value my time too much to waste it on repairing minor appliances. You get great pleasure from that activity. We are never going to agree on what constitutes a good product - you want a maintenance manual and lots of spares; I want no failures and no hassles during a useful life cycle. I think we agree on a love of old computers and the need to keep a few alive. And we may share pleasure in designing and building little systems. But I wonder if you enjoy playing with PICs and FPGAs like I do, since little documention on the innards is available. And I know we disagree strongly on use of the internet, saving old manuals and sending photos, scans, software etc. That requires technology you are not willing to embrace. I have to admit I'm hoping to meet you next year. I'll be retiring then and we are going to spend half our time in Colechester and the other half in California. We are going to explore a lot of England that I still haven't seen. And attend a few science fiction conventions, hit the famous book stores in Wales, check out pub food, sample the local beers and in general do the things we always wanted to do but were too busy. Billy

19 years, 5 months

1702 EPROM's

by Fixer7526＠wmconnect.com

Hello, Would you please post the following message. I am looking for someone who can copy 1702 EPROM's. Contact me at Fixer7526 at wmconnect.com . Thanks, Alan

19 years, 5 months

Free: Kennedy Tape drive and rack

by rick＠rickmurphy.net

I've got a Kennedy 9000 9-track tension-arm tape drive (800/1600 bpi dual density) installed in a 5-foot tall rack. The rack has side and back panels as well as some covers for the front. The drive was working a few years ago so it's complete but I have no idea if it's still OK. I've got the documentation including print sets, etc. It's available free for pickup in the Fairfax county Virginia area. We'll need to remove the drive from the rack to get it out of the basement unless you bring some help :-) -Rick

19 years, 5 months

got an HP 9915A computer

by vax9000＠gmail.com

Haven't decided what to do with it yet. Got a DEC VT240, no monitor, no keyboard. free for shipping. Got a VAXSTATION 3100 model VS42??, there is a crack on the face panel. Looks good other than that crack. No disks. Free for shipping. vax, 9000

19 years, 5 months

got a rare 386 CPU

by vax9000＠gmail.com

A80386EXI, step B http://wiggum.4amlunch.net/~vax9000/PHOTOS/DSCN6606.JPG

19 years, 5 months

Build your own Apollo Guidance Computer

by aliensrcooluk＠yahoo.co.uk

--- Brent Hilpert <hilpert at cs.ubc.ca> wrote: > Billy Pettit wrote: > > **>> snip <<** > > I have a web page > (http://www.cs.ubc.ca/~hilpert/e/gates/index.html) > where I'm accumulating the diversity of symbols th at > have been used for > logic gates. If you have a scan or reference for t he > Cray/6600 symbols I'd be > interested in adding them. > Thanks for posting that. Regards, Andrew D. Burton aliensrcooluk at yahoo.co.uk

19 years, 5 months

HP 2000F'

by MGemeny＠pgcps.org

The simplest distinction between HP2000 F and Access is that, F and everything prior (As I recall) used KILL-name (or KIL-name) to delete a program so that one could save a new version of it. Access changed that to PURGE-name (or PUR-name) for better "Political Correctness". I even remember that the system at Laurel HS in Laurel MD "Patti", made this change in the summer of 1976. Does ether "kill" or "purge" ring a bell to you, Richard? I see many people telling wonderful stories about HP2000 systems. If some of the others could also share with us where the systems were located, someone else in the group may also remember some of them. Three of the original HP2000 operating systems are running under SIMH, version E, F, and Access. If anyone is interested in booting up a real HP2000 TSB OS on simulated hardware (E should run on Unix, all three should run on Windoz), you may want to checkout: http://tech.groups.yahoo.com/group/hp2000family/ The links to the E and F Zips are in the links section of the group. The group is a good place to ask support questions about the OS or the simulation. New members are moderated to prevent spam bots from spamming us. If I can tell that you're a real person I'll take that off as soon as I see it, or you can call it to my attention by email. The Access Zip STILL has a real backup of a real system on it (sorry about that). So it is available by request. On the subject of Z999, I seem to recall that at least some of the systems before Access even had the HELLO program residing in Z999. As far as I have seen in the Access source Z999 no longer had any special privelages. Someone asked about backing up TSB E without a tape drive. The 7900 disk drive had one fixed platter and one removable platter. The system and A000 library was on the fixed platter, and user catalogs were on the removable platter. To backup, you first shutdown the Timeshare System. Then remove the top disk platter cartridge (containing the user libraries). Put a scratch cartridge in and copy the fixed disk to it. Then put the user data cartridge back in and copy it to the fixed disk platter (trashing your system disk). Then put in another scratch disk and copy the user data from the fixed disk to the removable disk. Then, put your backup of the system data back in, restore the fixed disk, then put your user pack back in and start up the timeshare again. Presto, you now have a backup removable platter containing a copy of the system platter and another with a copy of the user data. If course, when running on simulated hardware, tape drives are free, so we usually backup even TSB E to tape image files. The TSB E OS was distributed on two paper tapes, with a third tape for the loader. The ZIP files for the simulator contain images of the original paper tapes. Remember, the simulator is only simulating the hardware. Even on Access we are using an image of the original paper tape bootstrap to get the system running. The original operating systems don't know that they are not running on real hardware. Even for someone interested in building a real system, having access to all of the binaries and documentation in one nice neat package that is freely available and will even boot and run on a laptop, should be a helpful tool. It can help you get used to the system operator, system administrator and system analyst roles before you get your real hardware running. And besides, it's fun to "telnet 127.0.0.1" and do a CR LF CR LF and see "PLEASE LOG IN". If anyone knows or may be able to track down anyone who may still have an old HP2000 system back up tape, we would love to hear about it. We have had great success reading and reloading old tapes under simulation. Hope this helps, Mike Gemeny

19 years, 5 months

Cylinders versus tracks...

by Watzman＠neo.rr.com

A Cylinder is not a single point; it's the collection of multiple tracks that are all under the read/write heads whenever the heads are positioned over that cylinder. It exists only because there are multiple heads. However, while a double sided floppy drive does have cylinders, some systems did not take advantage of them and accessed the floppy drive using all of one side first, then all of the other side, rather than using cylinders (rather than tracks) sequentially. Both types of access are possible, and cylinder based access is clearly "better", but not all systems worked that way. Message: 31 Date: Fri, 22 Dec 2006 06:59:35 -0600 From: Jules Richardson <julesrichardsonuk at yahoo.co.uk> Subject: Cylinders versus tracks... To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org> Message-ID: <458BD6B7.8040100 at yahoo.co.uk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Out of interest, which is the correct terminology when defining a single point on a disk's surface - is it better to talk in terms of cylinders, or tracks? People often seem to talk about floppy drives in terms of tracks, heads and sectors (e.g. for an 80 cylinder floppy with two sides they'll still talk in terms of tracks 1-80 in conjunction with a side number, even though the media has 160 tracks in total) Talking in terms of cylinders seems to be generally the norm with hard disks though, and perhaps seems a bit more sensible - but remember that hard disk manufacturers are the people who introduced decimal megabytes into common use :-) Personally I prefer to talk in terms of 'surface number' rather than 'head number', as a given surface could conceivably have more than one head in order to improve media latency - but I'm unsure as to whether to use cylinder/surface/sector or track/surface/sector. It's all just semantics, but for the stuff I'm currently working on I'd rather go with the 'correct' version even if that happens not to be the one most commonly used... cheers Jules

19 years, 5 months

Cylinders versus tracks...

by Billy.Pettit＠wdc.com

* Jules Richardson wrote: Out of interest, which is the correct terminology when defining a single point on a disk's surface - is it better to talk in terms of cylinders, or tracks? People often seem to talk about floppy drives in terms of tracks, heads and sectors (e.g. for an 80 cylinder floppy with two sides they'll still talk in terms of tracks 1-80 in conjunction with a side number, even though the media has 160 tracks in total) Talking in terms of cylinders seems to be generally the norm with hard disks though, and perhaps seems a bit more sensible - but remember that hard disk manufacturers are the people who introduced decimal megabytes into common use :-) Personally I prefer to talk in terms of 'surface number' rather than 'head number', as a given surface could conceivably have more than one head in order to improve media latency - but I'm unsure as to whether to use cylinder/surface/sector or track/surface/sector. It's all just semantics, but for the stuff I'm currently working on I'd rather go with the 'correct' version even if that happens not to be the one most commonly used... cheers Jules -------------------------------------------------- Tracks was the original terminology when only one surface was used. For example on some of the early single sided floppies. Cylinders were used to describe a head switch to a new surface. The head switch would be very fast (faster than a one track seek) so continuous data could be recorded on the same track on different surfaces - in effect, a cylinder. So tracks is accurate even on multiple surfaces. But cylinders implies that data is written on all available heads before a seek is performed. With the advent of the embedded servo, tracks no longer line up neatly. A head switch may involve the new head seeking 10-100 tracks to get back to the same track number. Current state of the art is ~150K tracks per inch. So even a small difference is a lot of tracks. And 1 track seeks are now very fast, so it is rare to see controllers doing the cylinder concept. Because the usage and language has changed with time, the use of cylinders versus tracks depends a lot on the vintage of drive and controller. Cylinders were the most efficient way to use an SMD era drive with a dedicated servo surface. But they are performance lagging on today's drives. The amount of data on a track is variable and has been for many years. So the drive is divided into zones, which have a different amount of bits per track for each zone. Drives may have as many as 50 zones, ie 50 different numbers of bits per track. Modern drives often have a different number of tracks on each surface. So a single platter drive could have 2 different track counts, one for each surface. Thus current state of the art drives can have a huge difference in the number of tracks and amount of data on the surfaces. For example, a 100GB single platter drive may have 44GB on one surface and 56GB on the other surface. Because of this, you need a decoder program to even find what track you on. Cylinder and tracks don't have much meaning at the interface level. Consequently, we normally use LBA - Logical Block Address - and don't pay much attention to tracks or cylinders. Except when trying to physically view of certain spot on a disk. Billy

19 years, 5 months

Pertec 33xx and 34xx drives

by hamren＠sdu.se

Lars Hamren writes: Hi, Computer Automation LSI-2 machines, of which I have two, used Pertec D33xx drives, of which I have none. There is now a somewhat pricey Pertec D3421 drive on eBay. The $500 question is: will this drive interface to my systems? Does anyone have documentation on Pertec 33xx and 34xx disk drives? Does anyone know if 34xx can drives be used on systems designed for 33xx? Regards /Lars ------------------------------------------------------------------- Lars Hamr?n Tel...: +46( 46)189090 Svensk Datorutveckling Mobile: +46(705)189090 Vadm?llan 211 e-post: hamren at sdu.se S-225 94 Lund WWW...: www.sdu.se Sweden

19 years, 5 months

Extraneous Features (was: Re: Advice for tape drive repair...)

by mtapley＠swri.edu

At 22:00 -0600 12/21/06, Jules wrote: >Yes, but they're *there* for a lot of products, whether you want them or not. >If they're not there, and are optional extras, and you pay an additional fee >for them if you want them, fine. This is a bit unusual, but there are cases where the added features make it impossible to use the product. Cell-phone cameras are a case in point. There are places I work where I would not be allowed to carry a cell phone which has a camera. Mine doesn't, so I'm OK. Then there are cases (in software, usually) where an "added feature" means an entry point for abuse/breakage .... that affects more people. <busy erasing Spam at the moment....> -- Mark Tapley, Dwarf Engineer (I haven't cleared my neighborhood) 210-379-4635 Dwarf Phone, 210-522-6025 Office Phone

19 years, 5 months

Multibus II Card on eBay

by ken＠seefried.com

Dunno if anyone on the list is into Multibus II gear, but if you are you might want to grab this one: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190064943671 It's not a VME card, it's a 68030 Multibus II card. Very unusual. He's got a few other more pedestrian M-II card as well. Ken

19 years, 5 months

Cylinders versus tracks...

by blstuart＠bellsouth.net

> Out of interest, which is the correct terminology when defining a single point > on a disk's surface - is it better to talk in terms of cylinders, or tracks? I generally teach it this way. A track is the path traced by a single head during a rotation of the spindle. A cylinder is the set of tracks traced by all the heads for a single position of the arm. Thus specifying the cylinder number specifies the position of the arm. Specifying the head number selects the desired track from the set in the cylinder. > cylinder/surface/sector or track/surface/sector. It's all just semantics, but Track/surface is actually redundant since the combination of cylinder and head uniquely identifies a track. In other words, the track number implies the surface. As to the usage in the floppy world, I'd guess that it started with the old single-sided floppies. For them, a cylinder and a track were the same thing. Then for double-sided floppies, people tended to talk in terms of a track number on a side and didn't think in terms of cylinders at all. But on multiplatter disks, the concept of a cylinder becomes a lot more meaningful. Regardless of how many surfaces we have, it is the difference between our current cylinder number and the desired one that dominates the access time. BLS

19 years, 5 months

Bell 103 Datasets

by RodSmallwood＠mail.ediconsulting.co.uk

Yes that's it!! All of their stuff was that bright red colour. That reminds me... If anybody hears of a Newbury Labs VDU (M2480) up for grabs or sale they might let me know. I worked there in the early 70's and another one of the guy's from those days lives about a mile from me. rodsmallwood at btconnect.com 0118 971 4436 -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of John Honniball Sent: 21 December 2006 22:40 To: On-Topic Posts Only Subject: Re: Bell 103 Datasets Rod Smallwood wrote: > Priot to that UK acoustic couplers where available. I remember > connecting to a time sharing service (RSTS on an 11/70) using a > ModTech coupler whilst working on VDU design circa 1973. Was it by any chance this model Modular Technology modem: http://www.flickr.com/photos/11328208 at N00/329472291/ (orange-red acoustic coupler, model XAC3001, full or half duplex, 300 baud). -- John Honniball coredump at gifford.co.uk

19 years, 5 months

Searching cctalk Archive

by ksr＠krother.com

Is anyone else having trouble searching the CCTALK archive. I always get an empty search result. Thanks

19 years, 5 months

AP 120B

by kahrs＠caip.rutgers.edu

Now on epay: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320063237143&fromMakeTra… Looks very cool, but heavy. I have the manuals for this thing somewhere I think.

19 years, 5 months

Bell 103 Datasets

by RodSmallwood＠mail.ediconsulting.co.uk

Hi It was not mandatory to use BT modems but they were suppposed to be approved with a (BATB) sticker on the bottom. Both Hayes and USR produced UK versions. Plus there were some UK made modems eg Modular Techology & Dowty. Priot to that UK acoustic couplers where available. I remember connecting to a time sharing service (RSTS on an 11/70) using a ModTech coupler whilst working on VDU design circa 1973. Rod Smallwood -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Tony Duell Sent: 20 December 2006 23:59 To: cctalk at classiccmp.org Subject: Re: Bell 103 Datasets > In the UK at that sort of time you were presumably required to have a > GPO (later BT) modem and nothing else, but I'm afraid the web seems to > be rather I beleive so, since everything connected to the phone line had to be rented from the GPO. I can't help with dates, but I do have a few old ex-GPO modems in the collection. The Modem 2B is a large box (about 16" square and 7" high from memory. It's 300 baud, original and answer. The front panel opens by undoing 2 captice screws at the bottom and then hinging it up (there's a little 'stay' to keep it open). Insider are 4 plug-in modules -- PSU, Demodulator, Control, Modulator, with testpoints, fuses, and adjustments on the front panels. The modulator appears to be a VCO with switched control voltage. The demodulator has 'tobacco tins' which cotnain complex LC filter networks, and appears to work by mixingthe incoming signal with a lcoal oscillator, extracting the 'sum' frequency, and feeding that to a discrimiator circuit (similar to one of the standard ones used in FM radio receivers, I forget which). It's all discrete transistors and relays (in the control module), no ICs. The Modem D1200A is similar in construction and design (and seems to be the same case) but is 1200/75 baud (I forget which way round, it may well be the 'host' end of a Prestel link). The Modem 13A is somewhat later. It's a plinth that's screwed to the bottom of a type 746 telephone (one of the standard desk telephones of the 1970s). the phone has buttons to select voice or 'data' in front of the handset rest. The circuitry seems to use several metal-can (10 or 12 lead TO5-like cans) ICs that I know nothing about, and alas the schematic diagram inside the phone just shows the wiring to the extra switches and to the modem unit, no details of the internal circuitry of the modem itself. Again it seems to be 300 baud, probably originate only. -tony

19 years, 5 months

TTL Calculator Project

by Billy.Pettit＠wdc.com

Several months back, we talked about a calculator built from TTL. It came >from a 1970's article in Practical Electronics, an English Magazine. I had 7 requests for copies, which I mailed directly to the requestors. Apparently they disappeared into a black hole, because I didn't receive a single acknowledgement, let alone a thank you. So for those still interested, Al Kossow scanned my copy and posted it on bitsavers: http://www.bitsavers.org/pdf/practicalElectronics/digi-cal/Digi-Cal_Jul72-Ma y73.pdf Billy

19 years, 5 months

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test-drb