More on the Racal-Vadic VA3451S Auto-Dial Modem

A little searching around on the Googles turned up some information I didn’t already know about my beloved modem:

  • Racal introduced the VA3451S in 1982.  It retailed for $900.
  • The modem is based on the VA3400 protocol, which was developed by Racal and introduced in 1973, nearly ten years before the ’51S hit the market.  The protocol allowed full-duplex 1200-bps transmission over two-wire connections, a thing not previously possible.
  • Bell introduced its more-capable 212A modem three years later.  The 212A is incompatible with VA3400.  Fortunately, Bill Blue and Mark Robbins thought to include multiple protocols when they developed AE Pro.
  • Wang sold a re-branded version of this modem creatively called the WA3451S for its line of workstations and terminals.

And this, I was able to pull from the musty cobwebbed corners of my brain: the init string is S0=0 E1Q0V1X4&K3.  I know this because I had to key it in every time I loaded up AE Pro to wake the modem up.  Eventually, I discovered AE Pro’s awesome macro language and I never had to type it again, but not before it was scored into the gray fleshy folds of my brain matter.

Also, there’s a manual specific to the 3451S out there somewhere (that I never got to see since ours was a second-hand modem, inherited from my father’s place of work).  The manual goes into much greater depth on my specific model.   I’d love access to a PDF copy, if anyone can point me in the right direction.  Apparently, it’s part of a TOSEC collection, but I can’t locate it.

This old modem

As I was rooting through the storage unit the other day, in search of something entirely unrelated to anything Apple II’ish, I stumbled across my very first modem.  I thought I’d disposed of this thing years ago and was happy to learn I was mistaken.  I was almost as happy to learn that I’d had the sense to make sure I packed the massive power brick along with the rest of it. I despise proprietary power connectors for this very reason.  I don’t blame developers for rolling their own but I’m terrible at keeping track of them, especially as the years begin to roll by.  The worst offenders are the companies who don’t bother to mark the brick with information about what it’s intended to couple to.  But that’s another rant…

My father originally brought this home from work when the company he worked for, NCR, bought his engineering department a handful of Apple ///’s so they could put in extra hours at home on the weekend.  My dad and a few other key personnel each got one and every Friday night, he would pack that 26 lb monster and all its accessories into the family Opal, drive it home, unpack it again and set it up in his study.  On Monday morning, back it would go.

When NCR replaced their ///’s with shiny new IBM PCs, he got to keep the modem and it integrated nicely into the family II Plus (and later, IIe).

To get back on topic, I plugged it into my IIe to see if it still worked.  Spoiler alert: it did not, so I decided to take it apart for a little quick & dirty troubleshooting.  Here are some photos and notes I took.

(Click on the thumbnails for full-size images.)


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The Racal-Vadic Auto-Dial VA3451 300 bps modem.  This little baby and me, plus my hacked up copy of ASCII Express Pro, made one lean, mean BBS-in’ machine.  The manual states that this model could also do 1200 bps out of the box, but I specifically remember that it would only do 300 for the first few years we had it.  It wasn’t until I bought a PROM upgrade that the blazing speed of 1200 characters per second was unlocked.


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Self-test instructions are clearly delineated on the bottom of the modem.  Note the lack of screws holding the unit together.


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Back of the modem, showing the switches, phone and power cables and the 25-pin serial connection.


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With the cover off, we can see that the modem is a two-board device with lots of chips.

(More after the jump.)

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A look at an early Apple IIe

(Warning: I’ll be discussing topics that may seem extremely obscure and pointless to the casual visitor.  If you’re don’t find interesting the minor nuances in Apple II design, manufacturing and engineering over the years, this will likely be terrifically boring.)

A while back, I came into possession of an early Apple IIe and I thought it might be fun to post about it here.

This is Apple IIe serial number A2S2-01601.  The motherboard is a Rev. A, date-coded “8233″, in hand-written ink, which would put it mid-August 1982, several months before the IIe was announced in December of that year. Here’s a look at some of the chips and their date codes.

(click the ‘i’ for image captions and information)

Notes: The date code on the PCB, 8233, is the 33rd week of 1982, which (if we assume the week starts on a Sunday) puts the date of “manufacture” (probably when the board was assembled, rather than when the PCB was etched) between August 16 and 22.  Steve Jobs was 27 years old; Woz had just turned 32.

Older Apple IIs don’t necessarily match up with older power supplies, by serial number.  There doesn’t seem to be any rhyme or reason to how Apple decided which power supply went into which machine.

The “newest” chip in this Apple IIe is the MMU, with a date code of 8244, made eleven weeks after the rest of the PCB was assembled. I’m not sure if this means this batch of machines was assembled and then put on a shelf until the next shipment came in from Synertek, or if this particular computer had its MMU replaced at some point.  Judging from the pins on the chip, it doesn’t appear to have been serviced.

OKI Semiconductor used a 5-digit date code on the DRAMs that I haven’t figured out yet.  I can’t find a datasheet or manual describing how they did their encoding.  I believe that either the first two numbers, “24″, indicate the week of manufacture, and the “1″ is used for the year, assuming a 1980 decade, so these were made in the 24th week of 1981; or the first digit indicates the year “1982″ and the “41″ indicates the week, which puts them as manufactured right around the same time as everything else in this IIe.  OKI had two plants, one in Taiwan and the other in Singapore.  I suspect the “52″ and “97″ trailing numbers on the DRAMs indicate factory of origin, though I might be way off here.

Here’s a look at some of the interesting and unique case features:

(click the ‘i’ for image captions and information)

Here’s a video clip of Apple II historian and hardware expert Tony Diaz comparing this computer to Apple IIe A2S2-01345 during his “Apple II Road Show” session at KansasFest 2013.  Fascinating to see how different were their fates, considering how seemingly close they were in production order.

Tomorrow, I’ll post some photos comparing this Apple to a II Plus, as well as a later model IIe.

Try and try and…

Wherein, I outline my intention to present completely biased and unfair reviews of a few books designed to teach readers how to program in 6502 machine language, and perhaps learn a thing or two along the way.

I’ve complained at length in the past (don’t go looking for the posts here – I never bothered to restore any blog entries after that extended period of downtime) about the tendency of most 6502 assembly tutorial authors to simply throw the reader face-first at the brick wall of learning binary maths, usually within the first five to ten pages.

These “introductions” usually kick off with dire warnings in bold font of failure, destruction, and the promise of the fiery overturning of buses full of nuns and kittens, if the lessons are skipped without fully understanding them.  Following these proclamations of imminent doom, the reader is presented a paragraph or two of brief explanation and a couple of exercises one can use to show off their new-found prowess to friends.

But what if you didn’t understand something?  What if the answers you come up with to the exercises don’t match what’s in the book?  You could try to read the lesson again, but without a corrective guide, you’re probably going to end up at the same conclusions.

You could plunge ahead, but… Well, you *do* remember those warnings, don’t you?

And so over the years, I’ve accumulated a pile of books, all of which have fifteen to twenty pages of well-worn material, and are retail-shelf new that point.  As I look through them again, one thing is clear above all else: the information is presented in a nearly-identical and uniform manner: learn this binary math stuff before you proceed.  There’s a reason for this, and it’s a simple one: it works.  Or it works well enough to get budding assembly language programmers on their way to greater coding fame.  Countless Apple II programmers have followed these well-trodden paths before me and have emerged at the other end, wiser, smarter and with optimized code flowing forth from them like a river.

The inevitable conclusion is the problem must be with me.  This is a challenge I’ve been unable to overcome.  I haven’t been able to make the connection between the lesson and the problems.  The data seems to make perfect sense as I read through it, but my answers to the exercises are invariably wrong and I can’t tell you how I got there, or where the error was made.  Whether it’s that I’m not processing the lessons logically, or that this is a thing I’m simply not smart enough to learn, one of the flyrods is going out of skew on the treadle between the page and how my brain processes what I’m seeing.

One solution then is to try again, this time taking care to analyze the lessons and try to divine how I absorb what I think is being taught, and see if a single point of failure emerges.

These are the books I’ve got on my shelf and I’ll be trying each one, documenting as I go.  And who knows?  Maybe I’ll get lucky and it will just click on one day like a light-switch…  Nah, nothing is ever that easy.

  • Apple Machine Language for Beginners, Mansfield
  • Assembly Lines: The Book, Wagner
  • Programming the 6502, Zacks
  • Apple Machine Language, Inman & Inman
  • How to Program the Apple II Using 6502 Assembly Language, Hyde
  • 6502 Assembly Language Programming, Fernandez, Tabler & Ashley
  • The Visible Computer: 6502

And a few other online resources and guides, such as Nick Morgan’s Easy6502 guide. I’m going to have a go at Wagner’s book tonight, since someone recommended it in the comments of the my previous post about this topic.  I expect I’ll have more to say tomorrow.

Happy Birthday to us!

The final issue of Ryan Suenaga’s newsletter, A2 News and Notes appeared in December 2006. His Apple II online services “dirt sheet” The Lamp! survived longer, finally disappearing after the August 2007 issue.  In my view, the demise of these scions of computing publishing marked the end of a lineage of publications dedicated to chronicling Apple II history, stretching all the way back to the forums of GEnie, CompuServe, The Source and so many other online outlets. These were places where users so like myself dialed-up, reached out and found a wide world of like-minded people who shared an intense and occasionally unreasonable love of the products of Woz’s imagination.  Places to go to find technical help with that bug you just couldn’t solve at 3 AM, or share a joke and a laugh over a moment in a door game, or complain about Apple’s treatment of the II to people who understood exactly what you meant.  The cancellation of The Lamp was the end of a certain tradition of timely news updates, reviews and information about my favorite computing platform and the people who used it.

Don’t get me wrong, I love Juiced.GS.  In fact, I love it so much, I’ve written a dozen or so articles for it, and spent the better part of my free time one month converting original proofs of the first few years of its publication to a digital form, to ensure their preservation and availability to future generations of hobbyists and digital historians.  The rest of that free time was dedicated to building a spreadsheet to index the articles in those early tomes.  A web-based descendant of that catalog can now be perused here. But Juiced.GS is a quarterly publication, which means that it can’t maintain an effective focus on up-to-the-minute Apple II news.  Sure, notable items found a place in the “DumpinGS” column, but it wouldn’t make sense to try to print the many minor happenings and time-sensitive stories that still mark just how vibrant and exciting our little corner of the vintage computing hobby still is, months after they happened.

“Wait!” you cry, “Blogs like A2Central and Call-A.P.P.L.E. do exactly that!” I agree.  Believe me, there’s nothing more exciting than to see a post announcing a new run of CFFAs or Uthernet cards and rushing over to their respective digital stores to throw my dollars at them before they sell out.  But blogs are oriented to giving you the here and now, the current, the new and shiny and don’t always do a good job of making easily available a record of events as they slip further into our past.  Blogs go away, sometimes without notice, taking their histories with them into the nothing.  Databases become corrupt and entries are lost, or don’t survive a CMS upgrade.  Sites get hacked.  Sysops ragequit and delete everything.  And sometimes, their search engines just plain suck.  The information is as good as lost if it’s inaccessible.  Who has time to spend these days, clicking through page after page of blog entries trying to find something that may have happened in late 2007, or early 2008… or was it 2009?

Ryan’s newsletters were an immensely useful resource at the time of their publication, and remain so as an easily accessible, searchable historical record of that era.  And in September 2007, they were done.

It was with these thoughts that I registered, intending to find a collaborator and relaunch some sort of Apple II news service to provide timely information in a format that met my requirements.  I hadn’t thought much beyond this – who, how, where to get the information without just cribbing usenet posts and entries on A2Central – but I felt it needed to be done.  And if no one else was interested, I’d at least have my own record that I could reference, because as my wife will tell you, my memory is terrible.

One thought that I kept coming back to was that a podcast might fit my designs nicely and would carry on the torch of Apple II journalism in a relatively new and interesting format.  Instead of just text, I could incorporate music, interviews, soundbites – things Apple II fans could get into and enjoy.

But here’s the thing.  I’m not very interesting.  I don’t have much personality and my voice is sort of nasal and pinched.  There was no way I could do by myself what amounted to an internet radio program that anyone would want to listen to.  And so I pushed all this to the back of my mind to percolate for a while.

And that’s about when Ken reached out to me as he was compiling his list of Apple II-related domains.  We started brainstorming how an Apple II news service would be defined, and as we did, it became clear that podcasting was the future of my dream.  Details started to emerge in the flow of conversation.  Neither of us had the time to do a weekly show and back then, we were …. well, okay, I was inexperienced at the painstaking time-suck that is editing audio, so it took much longer than it does these days.  We weren’t always the lean, mean podcasting machine we are today.  The streamlined, efficient Apple II media empire that is the Open Apple podcast did indeed have humble beginnings.  We wanted a structured format because so many podcasts that go the route of open-ended conversation lose focus and listener interest.  We wanted a rotating guest chair as our third host because that’s automatically at least a few minutes of fresh material each show. (I’m lazy and I work hard to minimize the amount of creative effort I have to put into a project.)  Not all of those big ideas worked out, though.  I recall that we wanted to keep it under an hour or so.  You can see how well that worked out.

And from there, we started to assemble the pieces.  Ken recorded a Rockhurst student reading a variety of scripts and samples (to often-hilarious effect) and we had our voice-overs.  He conscripted Peter Neubauer to handle our artwork.  He found us some great music we could cut up for bumpers between segments.  He got started building the website… Hm.  Come to mention it, I don’t remember doing all that much.

Ken had been collaborating with Andy Molloy on a number of Apple II projects over the years and so it seemed a natural choice to have him join us for our first recording.  That first session was difficult and uncomfortable and after we wrapped on that cold January afternoon, I discovered that my audio track was corrupt.  And so we did it all again.  There were problems with my audio.  None of us really sounded like we were having fun.  I remember being particularly nervous, a thing you can probably detect in the way my voice gets high and I talk faster than normal.  I don’t honestly know how I sound though.  I haven’t listened to those first shows since they were published.  Frankly, I’d appreciate it if you didn’t either but they’re still out there, if you must.

The funny thing though is despite how rough that first episode sounds, the response from the community was very positive.  So much so that we decided to do another. And another. And…

And that was three years ago this month.  Our little show has continued to grow and mature and improve over the 36 months we’ve done it, right in step with the life of the community we chronicle.

This podcast has given me so many things.

The hardware geniuses continue to blow us away with new stuff that takes the Apple II to places we’d never dreamed, and they come on the show to share that with us.

Software wizards like Sheppy and the guys at Brutal Deluxe still dazzle with their creativity and we get to report on it.

When Steve Jobs died, Open Apple was “on the air” hours after I first heard the news on the radio as I was driving home from work, and we shared some very real emotional moments.

Closer to home we were able to process our common grief when a respected member of our community died an untimely death.

An attempt to get Woz to join us for an episode of Open Apple lead directly to his surprise appearance at KansasFest last year.  I got to hang out with Woz!

The past three years have been filled with so many moments like these that I’d not have been able to otherwise experience, and I will always cherish them.

Through Open Apple, I’ve made new friends and strengthened my bond with others.

There were times when my frustration and anger got the best of me and all I wanted to do was quit the hobby and push my Apple II’s off a roof top.  My commitment to Open Apple kept me coming back and allowed me to move past those dark moments.

I’ve been honored to be a part of all this and despite some behind-the-scenes tantrums and wavering by a certain host who lives in Denver, I can’t wait to see what the next three years hold for the Apple II, for its amazing community of users, hobbyists and fans, and for Open Apple.

You can find Ken’s better-written, shorter story about the rest of the story here. (Maybe I should have opened with that… Good on you if you’ve read this far.)