test-drb

test-drb@ccmp.vtda.org

101090 discussions

Garbage on screen when using real VT100 on emulated PDP-11

by cctech＠beyondthepale.ie

> > The VT100 doesn't need padd characters IIRC (VT05 and VT52 definitely > do), but it uses a signalling scheme to tell the host that it's > internal buffer is full. This signalling scheme can be either in the > hardware signalling (DTR/CTS) or it can be XON/XOFF (DC1/DC3) control > characters in the data stream. > According to my VT102 manual, DTR is only turned off when the terminal is offline or performing a line disconnect. It doesn't seem to turn off DTR or any other signal in response to the input buffer becoming full. Under "Input Buffer Overflow Prevention", it goes on to say that there are three methods of input buffer overflow prevention and lists XON/XOFF, fill characters and low speed operation. A table shows the requirement for fill characters for various functions at various baud rates. It suggests that all functions require at least one fill character (null) at 9600 baud, even when not in smooth scroll mode. Regards, Peter Coghlan

13 years, 1 month

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

Now now Mardy. We can disagree w/o being hilarious. ------------------------------ On Tue, Feb 26, 2013 7:08 PM PST Mardy Marshall wrote: >Raspberry Pi - The Chia Pet of Personal Computers > >-Mardy >

13 years, 1 month

WAMECO FPBC-1 photo mask images

by nekonoko＠mac.com

Does anyone have any photos/drawings of the WAMECO FPBC-1 photo mask for the FPB-1 front panel board? I'm planning on recreating one as finding a stock photo mask is likely impossible at this late date. Thanks much, Pete Plank

13 years, 1 month

Looking for: SWTPC MP-S Serial Interface

by chrise＠pobox.com

On Wednesday (02/27/2013 at 09:58AM -0500), Bill Sudbrink wrote: > > > > I have a SWTPC 6800, but it came with the MP-C. I was thinking of > > building an MP-S with an additional baud rate clock, to get a higher > > speed than the MP-C. > > I may have a spare MP-C. You do know that SWTBUG/MKBUG will operate > an MP-C in slot 1? You don't "need" an MP-S to get your 6800 up. yes-- as I noted to Josh in a private message, SWTBUG would be required to run the MP-S as the console. The original SWTPC 6800 design used MIKBUG and the console interface was an MP-C. SWTBUG was released later as an upgrade ROM and it could support either an MP-C (original equipment) or an MP-S (upgrade) as the console. So, you really need to confirm which monitor ROM the system has to decide what you can or need to do for the console interface. Chris -- Chris Elmquist

13 years, 1 month

For Sale: Macintosh SE/30 and Apple IIGS Monitors

by slandon110＠gmail.com

Hate to part with this one, but it never gets used Mac SE/30 68MB RAM 80MB HDD Ethernet Card Apple Extended Keyboard II Spare 2GB HDD so you can upgrade it. This is one of the models that will run A/UX and NetBSD $300 shipped insured via USPS Priority mail. Also have 15khz Apple IIGS monitors for $50 shipped each

13 years, 1 month

Looking for: SWTPC MP-S Serial Interface

by derschjo＠gmail.com

Subject line says it all -- I picked up a-nearly- complete (and very very extremely dirty and full of mousedetritus) SWTPC 6800 but I'm missing the MP-S serial interface (which will eventually be necessary to doanything too useful with it once I've given the rest of the machine a good soak). Anyone have one going spare or have any leads? Thanksas always, Josh

13 years, 1 month

Garbage on screen when using real VT100 on emulated PDP-11

by cctech＠beyondthepale.ie

> > > > OK, I'm stumped. I'd like to use a real VT100 as a terminal with an > > emulated PDP-11 running RT11. > > > > When the VT100 is connected to a real PDP-11, it works fine. When connected > > to the emulated PDP-11, garbage characters begin to appear on the screen > > when, say, doing a DIR command. > > > > The garbage always starts in exactly the same place in the DIR listing. > > After that, garbage characters (grey squares) become interspersed with the > > good text. > > Too high a data rate without flow control. Either enable Xon/Xoff on > both ends or > use hardware control (most PCs do not support that correctly). > > If all else fails set the baud rated to something slower till the > problem goes away. > My VT102 manual describes the grey hatched squares as the substitute character and says they are displayed when the input buffer is full and characters are lost. It also suggests that hardware flow is not available and the only solutions are XON/XOFF, fill characters (nulls) or low speed operation. I strongly suspect the VT100 behaves the same. Appendix E "VT102/VT100 DIFFERENCES" doesn't suggest otherwise although it does say that the VT102 uses a different numbers of fill characters. Regards, Peter Coghlan

13 years, 1 month

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

------------------------------ On Tue, Feb 26, 2013 8:16 PM PST Ethan Dicks wrote: >So the Internet was not invoked in the purchase of _my_ Pi. > >-ethan I may have heard about it on this list. But the next mention or the first was in a magazine, Linux Format probably.

13 years, 1 month

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

------------------------------ On Tue, Feb 26, 2013 6:45 PM PST Doc Shipley wrote > My first foray into hot rods was a carburetor swap, not a full engine >build. I'd never have finished a motor if I'd jumped right into the >deep end. But an entry point can be a Peter Norton book or something like it or interpreted BASIC. Some people, not you, are disgusted with anything done the old ways. To my knowledge, the only way to create a laboratory quality flat piece of cast iron is with a blasted chisel. Newer ways of doing things need to be persued of course. You have to anticipate critiques on a list such as this. I alluded to a discussion with another lister about a 14 year old kid learning how to fix crt based displays. Is there one person on this list who isn't impressed with such a mind? Same kid taught himself calculus. But maybe it's best to break him of that interest in such old crap. It isn't all twitter, facebook and the rest of the garbage with the youngsters and thank God. Nothing against Rpi, just that it's definition of hardware hacking differs from some. Although I generally have an interest in it, and more so after this discussion, there still remains a void when it comes to learning chip level interfacing, leggo style.

13 years, 1 month

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

------------------------------ On Tue, Feb 26, 2013 2:01 PM PST Doc Shipley wrote: > My take on the Raspberry Pi is that it offers EXACTLY what it claims to offer. A cheap, accessible ENTRY POINT into programming and/or hardware hacking. It seems to be more about high level hardware interfacing then hardware hacking in the purest sense - chip level interfacing. Building or modifying a sbc, even a very rudimentary one, from discrete parts is more of what I would expect, and what I did expect when I first heard of it. Or being able to add some sort of functionality, etc.

13 years, 1 month

Strobe plotter documentation or information?

by Carl.Claunch＠gartner.com

On 26/02/2013, Dave wrote: >I found another for sale here, but I can't really afford to buy it and >ship to the UP.... > >http://www.bonanza.com/listings/Strobe-Graphics-System-Plotter-for-Apple-II… I agree. I spotted that one as well when searching, but $499 is way too much to pay to get a manual. Carl ________________________________ This e-mail message, including any attachments, is for the sole use of the person to whom it has been sent, and may contain information that is confidential or legally protected. If you are not the intended recipient or have received this message in error, you are not authorized to copy, distribute, or otherwise use this message or its attachments. Please notify the sender immediately by return e-mail and permanently delete this message and any attachments. Gartner makes no warranty that this e-mail is error or virus free.

13 years, 1 month

Raspberry Pi

by lproven＠gmail.com

On 26 February 2013 00:50, Zane H. Healy <healyzh at aracnet.com> wrote: > > It looks like some sort of AROS distro might be an option as well. Ah, yes, I'd forgotten about that. Yes, the AROS team are working on an ARM version, but AFAIK, at the moment, it can only run loaded as an application running under ARM Linux with X.11 or possibly under QEMU. It cannot yet actually boot on ARM hardware. Given that the Rpi struggles a bit with graphical Linux anyway, it's not really an alternative at the moment. But if or when they ever do produce a native-booting version, that will indeed be an option. AROS is small, slim and fast compared to modern x86 OSs - although it's relatively feature-poor, and like the AmigaOS 3 that it seeks to replicate, it has no VM, no memory protection, no user security or anything. It does have a TCP/IP stack and Web clients, though.] At the moment, TTBOMK, there are 4 OSs that run on Rpi: * Linux, obviously, as used on 99% of Pis * RISC OS - a feature-complete port, but so far lacking graphics acceleration etc. * Preliminary just-about-booting ports of NetBSD and FreeBSD There'a a boot manager but I am not sure it can handle anything except Linux: http://www.berryterminal.com/doku.php/berryboot -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Tel: +44 20-8685-0498 ? Cell: +44 7939-087884

13 years, 1 month

Gates, Zuckerberg urge kids to code

by tom_a_sparks＠yahoo.com.au

" Microsoft chairman Bill Gates, Facebook CEO Mark Zuckerberg and Twitter creator Jack Dorsey are among the tech celebrities in a new video to promote the teaching and learning of computer coding in schools. Titled What most schools don't teach, the video released online on Tuesday begins with Zuckerberg, Gates and other tech icons recalling how they got their start in coding. For some, it was in sixth grade. For others, such as Ruchi Sanghvi, Facebook's first female engineer, it happened in college. Running less than six minutes, the video promotes Code.org, a non-profit foundation created last year to boost computer programming education. "The first time I actually had something come up and say 'hello world,' and I made a computer do that, that was just astonishing," recalls Gabe Newell, president of video game studio Valve. But it's not just tech leaders promoting programming in the video. Chris Bosh, a Miami Heat basketballer, says about coding: "I know it can be intimidating, a lot of things are intimidating, but, you know, what isn't?" Code.org was founded by tech entrepreneur Hadi Partovi, an early investor in Facebook, Dropbox and the holiday rental site Airbnb. The organisation aims to address a problem often cited by tech companies - not enough computer science graduates to fill a growing number of programming jobs. The group laments that many schools don't even offer classes in programming. "Our policy is literally to hire as many talented engineers as we can find," Zuckerberg says in the video."The whole limit of the system is there just aren't enough people who are trained and have these skills today." ?" - http://au.news.yahoo.com/a/-/world/16250929/gates-zuckerberg-urge-kids-to-c… --- tom_a_sparks "It's a nerdy thing I like to do" Child of the Internet born 1983 Please use ISO approved file formats excluding Office Open XML - http://www.gnu.org/philosophy/no-word-attachments.html Ubuntu wiki page https://wiki.ubuntu.com/tomsparks

13 years, 1 month

WTB: DEC Multia/UDB (DPS-75TB, 75.24 W) PSU

by marcogb＠xs4all.nl

Does anyone have a Delta Electronics DPS-75TB 75.24 W power supply unit, perhaps a spare one and willing to sell/trade it? To clarify, it's the one found in the Digital Multia/UDB, or the VX40 of mine at least. I may also be interested in a full Multia/UDB, maybe a VX41, or a gutted one even (as long as the PSU still works fine). I may also consider a similarly-sized DEC 3000. Thanks in advance. - MG

13 years, 1 month

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

------------------------------ On Tue, Feb 26, 2013 3:42 PM PST Liam Proven wrote: >On 26 February 2013 23:33, Liam Proven <lproven at gmail.com> wrote: > >I don't know how that got sent half-done! Did you send it from a pi? >> To a child born in the developed world this century, the Web is part >> of life, always there at megabit speeds, as ubiq > >... as ubiquitous as air. Computers have GUIs, windows, taskbars etc, >and come with a web browser, as does even a cheap basic old phone or >pocket music player. Games are real-time 3D, even ones on a cheap 2- >or 3- generation old games console such as might be given to >preschoolers to play with. > >No, a BBC Micro or anything from the 1980s is not a suitable teaching >tool. It is a flint axe when the kids grew up with sliced bread. It is >a dugout canoe when grandad and grandma go yachting at the weekend. nobody uses flint axes. But they do fashion numerous tools and even build their own boats sometimes. >The mere idea is laughably unrealistic. > >If you are teaching a kid to drive, you don't teach them how to build >the car first. But the first drivers of cars needed to know a lot more about them if they wanted successful outings. You don't need to know a single thing about mechanics to drive. But to be a mechanic.you do need to know how to dismantle and reassemble a car. The "kids" already know how to "drive", turn on their computers and do basic tasks. What in the world does that have to do with anything. >If you're teaching them to maintain a car, you don't teach them how to >design and construct an engine first. Another analogy that doesn't quite seem appropriate. >So, no, actually, tools like BASIC and assembly code have no >relevance today, not really. Because the days when a BBC Micro was a >computer are so long ago that these kid's *parents* don't even really >remember them. I took a class and my first foray into BASIC was on an Atari 400 w/membrane k/b. Rest assured I will never forget. >A BBC Micro is not a computer any more, because it is 2013 now. People >live in space and have a Dynabook containing the entire Hitch-hiker's >Guide to the Galaxy in their pockets - it is normal for them to have >access to basically the entirety of human wisdom, wirelessly - because >even their parents don't remember phones that attached to *wires >coming out the wall* - because these are things so cheap that even the >kids in India and China are getting them now. You engaging in delusion. At least 1/2 of the US still maintain landlines, in addition to mobile phones. If you haven't been in a hurricane lately you may not be able to appreciate their utility when cellular networks crap the bed. >Assembly code is equivalent to how to chip a sharp arrowhead from a >piece of flint. Every flippin thing that runs on any computer in the world is running assembly instructions. Assembler or analysis thereof is NEVER going away. >BASIC is equivalent to learning how to smelt iron. LOL and how many groups and community colleges are engaging in that these days. If you're unaware foundry work has seen quite a resurgence in the last 15 years. And the point being you still and for a long time will need people who understand the rudimentary elements and processes that make up the tools we use every day. If for no other reason they just are curious. How ironic that just today I had an offline conversation about a 14 year old kid who's fixing CGA monitors for extra cash!!! >And the Raspberry Pi is a kids' computer that is cheaper than giving >them that old dusty Pentium 4 in the attic, because [a] you'd have to >get the P4 working again and install software on it, [b] it's a huge >noisy ugly piece of *office equipment* and not something a kid would >want to play with, and mostly because > >[c] The Raspberry Pi costs less to buy than the electricity used by >that P4 running every evening for a significant chunk of a year. But it doesn't teach bare fundamentals. That's the point everyone is trying to make it seems. >-- >Liam Proven ? Profile: http://lproven.livejournal.com/profile >Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven >MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven >Tel: +44 20-8685-0498 ? Cell: +44 7939-087884 >

13 years, 1 month

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

------------------------------ On Tue, Feb 26, 2013 3:23 PM PST Dave wrote: >> Absolutely. I suspect for many people it appeals because it's a cheap computer, and they don't really have a particular use in mind for it (so it doesn't matter that it's rather middle-ground for so many situations). >> > >https://raspberryjamboree-es2001.eventbrite.com/# Being that at least it somewhat lends itself to general purpose computing, someone should devise a case, charging circuit, etc. that would facilitate the piecing together of a low cost portable/netbook, where more or less standard batteries, lcds, keyboards etc can be added.

13 years, 1 month

RGB -> VGA adaptors (was: Re: Tek 4317)

by rampaginggreenhulk＠yahoo.com

------------------------------ On Tue, Feb 26, 2013 3:12 PM PST Mark Tapley wrote: >Some searching on the Color Computer site leads to this: > >http://miba51.com/CoCo_VGA_Adpater.html > >Roy Justus' converter from 15.7 kHz RGB as generated by a CoCo3 to 31 kHz VGA. >At one point, another was available from Chris Hawks > >http://permalink.gmane.org/gmane.comp.hardware.tandy.coco/63638 > >I have no experience with either, nor any connection except being a >fellow CoCo user. > >Hope this helps. Everyone is building scan doublers these days it seems. Princeton probably made the first one. Amiga had at least one flicker fixer, which is a bit different, the issue there being correcting interlaced video.

13 years, 1 month

at least one of the best ways to learn computing was Re: Raspberry Pi

by rampaginggreenhulk＠yahoo.com

Ok ------------------------------ On Tue, Feb 26, 2013 2:59 PM PST Jim Stephens wrote: > >On 2/26/2013 1:42 PM, Chris Tofu wrote: >> I haven't looked at the pi much, besides reading an article some time ago somewhere. At first glance I can't see how it can help a person learn hardware. No clue on that one. >The way that it helps with education and learning is that instead of telling someone to go buy and dedicate a laptop or other machine to a lab purpose, and download say a DVD to load it one can tell them to obtain a Pi and an SD card image to boot it on. > >There are several examples of lab setups where this is already done both by attaching adapters to outside things (relay boards, etc.) and another which attaches to a breadboard. > >The pi is not going to be the focus of the vast majority of these things, but will be the computer vehicle that delivers the educational setup. > >It can be the center of a lesson say to learn to program things that require only what it has to interact with, keyboard, mouse an display, plus for the model b adding in a network. > >Instead of picking up $25 random ecycled machine this is intended to replace that role. Also if the need arises in the right setting it can be the focus of the lesson. I hear you. I never suggested it was useless, nor uninteresting. I find what I have learned about interesting myself. But as I stated in the other post it's not about h/w hacking as I define it, though it may be a valid very current use of the terms. >One suggested in these threads, "what not to plug into the gpio pins". Screwing up that lesson costs you another Pi. I suspect there will be people who will jump in and plug thing in randomly, but they won't get far. I suspect most people will figure out what to do with what is there. Ok. But blowing an IBM mainboard due to mishap could require a lot of chips LOL or maybe only a few.

13 years, 1 month

at least one of the best ways to learn computing was Re: Raspberry Pi

by rampaginggreenhulk＠yahoo.com

Where are you anyway? Canada or US? What about a clone? I might be able to find you one of those. And you're totally w/i your rights to decline, just please don't because it ain't an IBeeMer. Even an Apple might be a possibility. I can't control shipping costs, USPS isn't too bad usually, but maybe for 20-30$ I could rustle you up something. Would ship from 07731 NJ. Point taken though. But for as many people that truly want to learn discrete h/w, there is always something available for 100-150$. And often much less. One of the coolest projects I've seen to date is the Radio Electronics RE Robot brain, 80188 based. I have everything - schematics, artwork, firmware images, even a contact (named Chris!) who built the whole robot. Gernsback used to have a bbs. What I wouldn't do for those archives. But at least I have all the raw materials, and a "revolutionary" new way of making pcb's _at_home_, that works all the time I'm told. And the project is at least somewhat tried and true,being it was an actual board manufactured by Vesta Technology, who's still around. Hey Jules, I have a dead 5160 mainboard with some weird wire routing going on. For shippage. ------------------------------ On Tue, Feb 26, 2013 2:53 PM PST Jules Richardson wrote: >On 02/26/2013 03:42 PM, Chris Tofu wrote: >> Apples and IBMs are somewhat plentiful. > >Hmm, I'd love to find an Apple II or an IBM 5150 (or '60, but I'm not too bothered about having a hard disk). I don't think there are any even remotely nearby though, which means shipping (and worse still, the possibility of ebay prices)

13 years, 1 month

Raspberry Pi

by lproven＠gmail.com

On 25 Feb 2013 18:26, "Zane H. Healy" <healyzh at aracnet.com> wrote: > > The talk about the Acorn and RISC OS reminds me that I've been interested in one of these, primarily to run RISC OS. What is the recommended version, price, and place to get a Raspberry Pi from? > > I assume I want a "2.0 Model B 512Mb"? I've found a seller on eBay with this and they include a case for $57. If you want to keep it super cheap, try to find a Linux user upgrading to the 512MB version. 256MB is a vast amount of RAM for Risc OS, whereas it is not enough for a graphical Linux desktop. You really don't need half a gig for Risc OS, unless of course you want to run Linux as well.

13 years, 1 month

RGB -> VGA adaptors (was: Re: Tek 4317)

by mtapley＠swri.edu

Some searching on the Color Computer site leads to this: http://miba51.com/CoCo_VGA_Adpater.html Roy Justus' converter from 15.7 kHz RGB as generated by a CoCo3 to 31 kHz VGA. At one point, another was available from Chris Hawks http://permalink.gmane.org/gmane.comp.hardware.tandy.coco/63638 I have no experience with either, nor any connection except being a fellow CoCo user. Hope this helps. At 16:39 -0600 2/26/13, <Sander> wrote: >Message: 12 >Date: Tue, 26 Feb 2013 13:29:38 -0700 >From: Richard <legalize at xmission.com> >To: cctalk <cctalk at classiccmp.org> >Subject: Re: Tek 4317 >Message-ID: <E1UAR9e-0000zT-PL at shell.xmission.com> > > >In article <201302260715.r1Q7FiJL027219 at ls-al.eu>, > Sander Reiche <reiche at ls-al.eu> writes: > >> Richard <legalize at xmission.com> wrote: >> > >> > I have other Tektronix hardware from this time frame and the video >> > output tends to be standard RGB (possibly synch-on-green) BNC >> > connectors. >> >> I'm still pursuing this, but it's taking its time. >> > > Are there any good converters for RGB? Like to VGA? > >Based on this picture, it appears that it would have RGB BNC connectors. ><http://user.xmission.com/~legalize/tmp/vintage/tektronix/xd88/20120417_1304…> > >That implies synch-on-green video signalling. If you don't have a >synch-on-green RGB monitor, then you'll need an adapter to convert >that to VGA (which splits the synch signals out on a separate pin). >These shouldn't be too hard to find because synch-on-green was fairly >common. >-- >"The Direct3D Graphics Pipeline" free book <http://tinyurl.com/d3d-pipeline> > The Computer Graphics Museum <http://computergraphicsmuseum.org> > The Terminals Wiki <http://terminals.classiccmp.org> > Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com> -- - Mark 210-379-4635 ----------------------------------------------------------------------- Large Asteroids headed toward planets inhabited by beings that don't have technology adequate to stop them: Think of it as Evolution in Fast-Forward.

13 years, 1 month

OT: WWVB clock with silent movement

by aek＠bitsavers.org

We just went through another round of replacing battery clocks at the radio station and I've been going crazy trying to find one that is auto-set AND has a continous-sweep second hand. You can find a dozen Chinese manufacturers, but none in the US retail market.

13 years, 1 month

at least one of the best ways to learn computing was Re: Raspberry Pi

by rampaginggreenhulk＠yahoo.com

This follows Tony's reply. I have little knowledge of DEC stuff and no knowledge of Beebs. I was sort of surprised that a PDP-8e's boot sequence is very similar to a peecee's, but this is fundamental to computers really, and this I had to learn. Apples and IBMs are somewhat plentiful. The Commie 64 has a bit too much custom logic, even a Mac has less in reality. Not a huge Apple II fan, but it seems to have little or none. A 5150 mainboard has zero custom logic, not even a pal unless I'm mistaken (and there's validity in the argument that a smidgeon of custom logic enhances learning - in that it would be a comprehensive example). There are undoubtedly many examples that would nicely fit the bill (and if you wanted to FORCE yourself to learn and delve into assembler and whatnot, get a Tandy 2000! It don't run squat, besides a handful of items that were modified for it, bizarro scientific and accounting packages. Zork. Hooray. Conspicuous by it's absence on the list is Starflight! Why - why WHY!!!). I haven't looked at the pi much, besides reading an article some time ago somewhere. At first glance I can't see how it can help a person learn hardware. No clue on that one.

13 years, 1 month

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

------------------------------ On Tue, Feb 26, 2013 1:21 PM PST Fred Cisin wrote: >On Tue, 26 Feb 2013, Tony Duell wrote: >> But I do wonder jhsut who the Rpi is aimed at. Given that you need a PC >> and its peripherals (keyboard, mouse, monitor) to use the Rpi, I wonder >> if it wouldn't be simpler jsut to install a free C compiler on said PC, >> at least to learn programming. > >'twould make sense. >A generic 5160 is a fine machine to learn certain stages of programming >on. > > >but, in wasteful cultures, like we have here, can pick up a eMachines or >Packard Bell on the curb on trash day, and use it to flesh out a Raspberry >Pi? You know there might be a burgeoning demand for old eMachins and PBells soon. Or perhaps some should design a sbc that could take their place.

13 years, 1 month

OT: WWVB clock with silent movement

by tshoppa＠wmata.com

I think there was also an "Accutron" clock movement that could be driven from 60kHz. I think this movement was in at least some HP timekeeping instruments. In any event those were not truly silent either... put an Accutron up to your ear and you hear a high-pitched hum/buzz, not tick-tick-tick. -----Original Message----- From: Shoppa, Tim Sent: Tuesday, February 26, 2013 4:26 PM To: cctalk at classiccmp.org Subject: Re: OT: WWVB clock with silent movement Various "time-nuts" start off with GPS disciplined rubidium clocks, or radio clocks like WWVB, and derive a phase-locked 60Hz to run the old-fashioned 120VAC continuous-hand-movement analog and flip clocks (in my circle known as "NUMECHRON"s although I think the most applicable trademark was TYMETER). One example is: http://leapsecond.com/pages/atomic-nixie/ Obviously an HP 3325B is overkill as a 60Hz synthesizer but you get the idea. If you have WWVB carrier, 60Hz is just dividing by 1000, no funny numerator/denominator stuff.

13 years, 1 month

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test-drb