TweetFollow Us on Twitter

Jul 86 History
Volume Number:2
Issue Number:7
Column Tag:Historical Computing

The Famous TV Typewriter

By Dick Heiser, Industry Pioneer, On the Great Peace March

A Cooperative Venture

Sometimes the teamwork that makes a successful product is hidden, sometimes it's visible. In the case of the Macintosh, it's both hidden and visible- the names are molded into the inside of the case! The tv typewriter (TVT) was the work of four independent people. Don Lancaster, Dan Myers, Josef Rosenthal and I worked in succession to design it, to produce it as a kit, to modify it into a proper computer terminal, and to document the information. Each of us brought the product closer to the customer by making it easier to build and more useful.

Mother of Invention

The Altair personal computer didn't include a built-in video terminal. Video terminals sold for $1500 or more, until Lear Siegler introduced their $995 "dumb" terminal. But even that Lear Siegler terminal was an expensive accessory for a personal computer. Used Teletype model 33 teletypewriters were expensive too; good ones sold for $800 or more. Teletypes are like Volkswagens- they're slow and noisy, but they hardly depreciate, and they last forever.

Everybody who built an Altair needed a low-cost terminal for it. The "TV Typewriter 2" from Southwest Technical Products Company emerged as a probable best buy. [I had one. It was great! -Ed.] The TVT-2 kit cost about $275 by mail. Adding a keyboard, power supply, and serial interface raised the price by another $100.

Don Lancaster - Designer

"Don Lancaster writes books". That's how the designer of the TVT describes himself. He has written about a dozen electronics books. Many are still in print long after lesser technical books are gone. He's also a volunteer fireman and occasional forest ranger.

His Incredible Secret Money Machine is a wonderful career guidance book. Basically he suggests:

• Work for yourself.

• Do something you can throw yourself into wholeheartedly.

• Maximize the value you personally add to your product.

• Look for leverage and royalties.

• Don't invest lots of money in a new business.

When I referred to this book at the 1984 Hackers Conference, the audiance interrupted to cheer. Lots of top hackers know this book! Lancaster illustrates his advice by talking about himself. As an example of leverage, he explains that when he designs an electronics project, he writes a magazine article about it, licenses the kit for a royalty, and uses the articles as a book chapter. Don's TTL Cookbook and TV Typewriter Cookbook were best-sellers in my store.

Don Myers warned me "Don doesn't like to chat. In fact, he doesn't always answer his phone. He's as likely to sleep days and work nights as the other way around." When I called Don's unlisted number, he turned out to be quite friendly and open. He even told me what he planned next for the TVT's number 3, 4 and 5! He planned to lower the cost, and add color, to develop a terminal more like an Apple II. I tried to talk him into more characters per line and lower-case letters, because of my interest in computer text editing. Don was on a better track than I was.

TVT Design

The TV Typewriter-2 displayed 16 lines of 32 upper-case characters in a 5x7 dot matrix. The main circuit board was about 11 inches square, with a daughter board for screen memory, and optional boards for serial or parallel interface and manual or coded cursor movement control. It had connectors for a parallel ASCII keyboard, power supply, and video monitor.

The TV Typewriter-2 was an improved design. Lancaster used considerable expertise to generate an accurate, standard video signal. He was proud of the rock-steady video. The TVT was not really a computer terminal, however. For instance, new lines of text overwrote old text, so the ends of longer old lines showed alongside the new lines. The TVT was a video generator, suited for titling and announcements via closed-circuit tv, like the ones in hotels, theater lobbies, and airline terminals.

Dan Myers - Kit Producer

Dan Myers presided over the Southwest Technical Products Company in San Antonio, Texas. His company paid a royalty to Don Lancaster for the right to sell TVT circuit boards and kits. He advertised in magazines like Popular Electronics, because the TVT was an electronics project rather than a computer peripheral.

Dan took the printed circuit layout from Don Lancaster and had boards made. He prepared bags of integrated circuits, resistors, capacitors, and connectors. He printed a brief manual with layout diagram and schematic. He also bought the rights to a parallel ASCII keyboard design.

I've never seen Dan in person, but we've learned a lot about each other by talking on the phone and by doing business together. Dan is a "no frills" businessman, but he won't cut corners that he considers important. He wants to hold down costs so he can sell low cost products. Don Lancaster warned me to expect very short discounts, maybe ten percent or less, from Dan. I felt very lucky to negotiate a twenty percent discount, and preferred to do all of my business directly with Dan. Sometimes I wondered if he was a one-man show back then.

Unlike MITS and Heathkit, Dan charged extra to fix your machine if it didn't work. Dan and Don were well-matched to collaborate: they both wanted to control costs first and add features second.

The following year, Dan bought rights to a Motorola 6800 based computer design. He evaluated it on the basis of memory size, clock speed, instruction set, and price. His 6800 computer was a fantastic hardware value. He advertised it in the major computer and electronics magazines, and signed up dealers. It was a brave design. Unlike the MITS and IMSAI computers, it had no rows of switches and flashing lights. It used a "software front panel" which was the Right Stuff; better and cheaper.

His one big mistake was to apply his "no frills" attitude to software. Too bad. As Portia Isaacson once said, "After you consider the software available for a particular computer, the next most important consideration is the color of the cabinet!" Software was a hard lesson for Dan.

The TVT Kit

When you opened the five cardboard boxes for your TVT, serial interface, keyboard, power supply, and cursor control board, your emotions reflected your electronics expertise. The printed circuit board was a first-class piece of goods; fiberglass, two-sided with plated-through holes. You had to identify the parts by the codes printed on them. The only decoding information was a layout diagram for chip replacement, and a color-code list for resistors. Do you like Molex connectors? One early customer put the connectors on backwards, but they're cheap and they work.

The keyboard circuit was plated on only one side, so you had to solder on perpendicular "bus bars" to stiffen it and to supply the horizontal traces. Too little solder and the bus bars came loose. Too much heat and the plastic keyswitches would melt. It was definitely a challenge for newcomers!

The keyboards weren't good enough at first. More expensive keyswitches, more special characters, and improved circuit board layout helped, but these low cost keyboards were susceptible to static electricity burnouts.

Left as an exercise for the kit builder was the problem of boxing this collection of boards, figuring out which polarity of the keyboard strobe the TVT expected, and finding a video monitor. [Hitachi made a great little 9 inch montor, the 905, that was very popular. -Ed.]

Josef Rosenthal - System Engineer

Joe worked as a programmer for the System Development corporation (SDC) in Santa Monica. He built an Altair and a TVT early in the product life cylce. That means I sold him the stuff before it worked together properly.

Smiling Joe looked at the misfits between the computer and the TVT as a puzzle. He came by the store often to find out the latest developments and to share his discoveries.

Three problems fascinated him. First, the TVT was slow: its serial interface operated at only 10 characters per second. It was probably intended to connect TVT's to the teletypewriters rather than to computers. Joe wanted the interface to work ten times as fast.

The second problem has been mentioned above: ends of old lines of text remained on the screen beside the new lines. Listing a Basic program resulted in a gibberish mixture of text. Joe worked on a way to erase each line or screen before starting to write on it, or to erase to the end of each line before responding to a carriage return character.

The third problem involved taking advantage of a design feature. Don Lancaster provided two screens of video memory, and the TVT filled them alternately. We wanted to be able to switch screens, to review previous data.

Joe was the only one of us who worked for free. He was an enthusiast: excited, happy, full of possibilities, curious, experimental. He solved all three problems.

TVT Modifications

Speeding up the interface turned out to be easy. Joe examined the schematic, discovered a divide-by-nine counter in the clock circuit, and jumpered it out. The 110 baud circuit (10 characters per second) would now operate at 990 baud, an unlikely speed. No problem: Joe calculated what combination of jumpers would make the counter in the Altair's serial interface work at 990 baud, and viola, the nine-times speedup worked!

Another magic jumper solved the jumbled lines problem. Joe ran a jumper from the linefeed code to a circuit point which caused erase-to-end-of-line. Sure enough, it worked! Each time the terminal advanced to a new line, the new line was cleared. Now the TVT worked as a proper video terminal.

Joe further experimented with the screen switch logic. He could have added integrated circuit chips to switch from one screen to the other and vice versa. Instead, he directly wired a keyswitch to a screen selector toggle input. Each time you pressed that key, you delivered a random jolt to the selector toggle. No debouncing! I thought it would feel frustrating to operate a random switch, but it worked fine! If the screen didn't switch, I'd hit the button again. No sweat.

Joe also assigned key codes to make the cursor controls work right, and figured out keyboard jumpers to accomplish this. A few more jumpers supplied special characters like the caret or up-arrow, used in Basic programs. Joe accomplished magic: something for nothing. Not adding parts is a characteristic of elegance and of good hacking.

Dick Heiser - System Integrator

I was the last member of this "gang of four." As the person responsible to the customer for a successful project, I wanted to tie together what Don, Dan, Joe and others had discovered. At IBM, I'd learned that, "you're not through until the paperwork is done."

Earlier, I'd written a useful booklet of tips for building the Altair computer kit. The TVT booklet suggested which kits to obtain, how to orient connectors, gave advice on making the keyboard strong and reliable, and illustrated cuts and jumpers for strobe polarity, clear newline, screen select, special characters, cursor control and serial speed-up. It showed how to jumper the MITS serial board for 990 baud.

I had to revise this booklet as we learned more, and when improved keyboards became available.

In addition to the booklet, we sold a kit of extra parts, including chip sockets, keyboard cable, fuse, switch, screws and grommets. We also tried to sell cases for the TVT. Unhappily, metal-bending is a low-tech art, and we could not find a supplier able to consistently deliver quality. We helped people obtain a video monitor, too. We reprinted an article on converting tv's and we sold converted tv's and closed-circuit monitors.

TVT Complete

The manual overcame stumbling-blocks associated with the kit, and showed how to make a good $400 video terminal. The design and the chips were good enough that, armed with the advice in our notes, most customers were successful in building a TVT that worked right. Customers found the improved TVT easy to build. Our confidence at the store increased because our recommendations worked so well.

Using the TVT

For several months before we bought a cash register, I balanced the receipts with the comptuer. I used the TVT to operate the Altair, with a simple Basic program.

The video terminal gives a computer its "feel". It's "where the rubber meets the road." The TVT had a good feel. It's big letters (32 characters per line) were highly visible. Sometimes I like lots of little characters on the screen for context, but usually big characters are visually more relaxing. Naturally, the Macintosh is superior here, allowing either size. See if you like writing your draft copies with a larger than normal font next time.

The TVT's full-stroke keyboard allowed confident typing. Computer wizard Rick Shiffman would bang the keys so hard that weak keyboards would simply break. Thus Heiser's Fifth Law: keyboard bashing reflects user confidence- or poor software design!

TVT's Fate

Our modified TVT was the "state of the art" for only a year. Then, memory-mapped video boards for the Altair came along. These character-oriented displays worked like the Apple II. A dedicated area of computer memory held ascii codes to drive a character generator.

Polymorphic Systems and Processor Technology produced good memory-mapped video boards. This was before the era of the CP/M operating system, so softwre device drivers were not used. Each program had to be individually modified for memory-mapped video. Soon, memory-maped video took over, offering speed, compactness and economy, better suited to the powers of personal computers.

In it's day, the TVT was a key to making the Altair work right. I'm proud of the result, happy that our collaboration worked out so well. Besides which, it was fun!

 
AAPL
$119.00
Apple Inc.
+1.40
MSFT
$47.75
Microsoft Corpora
+0.28
GOOG
$540.37
Google Inc.
-0.71

MacTech Search:
Community Search:

Software Updates via MacUpdate

Skype 7.2.0.412 - Voice-over-internet ph...
Skype allows you to talk to friends, family and co-workers across the Internet without the inconvenience of long distance telephone charges. Using peer-to-peer data transmission technology, Skype... Read more
HoudahSpot 3.9.6 - Advanced file search...
HoudahSpot is a powerful file search tool built upon MacOS X Spotlight. Spotlight unleashed Create detailed queries to locate the exact file you need Narrow down searches. Zero in on files Save... Read more
RapidWeaver 6.0.3 - Create template-base...
RapidWeaver is a next-generation Web design application to help you easily create professional-looking Web sites in minutes. No knowledge of complex code is required, RapidWeaver will take care of... Read more
iPhoto Library Manager 4.1.10 - Manage m...
iPhoto Library Manager lets you organize your photos into multiple iPhoto libraries. Separate your high school and college photos from your latest summer vacation pictures. Or keep some photo... Read more
iExplorer 3.5.1.9 - View and transfer al...
iExplorer is an iPhone browser for Mac lets you view the files on your iOS device. By using a drag and drop interface, you can quickly copy files and folders between your Mac and your iPhone or... Read more
MacUpdate Desktop 6.0.3 - Discover and i...
MacUpdate Desktop 6 brings seamless 1-click installs and version updates to your Mac. With a free MacUpdate account and MacUpdate Desktop 6, Mac users can now install almost any Mac app on macupdate.... Read more
SteerMouse 4.2.2 - Powerful third-party...
SteerMouse is an advanced driver for USB and Bluetooth mice. It also supports Apple Mighty Mouse very well. SteerMouse can assign various functions to buttons that Apple's software does not allow,... Read more
iMazing 1.1 - Complete iOS device manage...
iMazing (was DiskAid) is the ultimate iOS device manager with capabilities far beyond what iTunes offers. With iMazing and your iOS device (iPhone, iPad, or iPod), you can: Copy music to and from... Read more
PopChar X 7.0 - Floating window shows av...
PopChar X helps you get the most out of your font collection. With its crystal-clear interface, PopChar X provides a frustration-free way to access any font's special characters. Expanded... Read more
OneNote 15.4 - Free digital notebook fro...
OneNote is your very own digital notebook. With OneNote, you can capture that flash of genius, that moment of inspiration, or that list of errands that's too important to forget. Whether you're at... Read more

Latest Forum Discussions

See All

Lucha Amigos (Games)
Lucha Amigos 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Forget Ninja Turtles, and meet Wrestlers Turtles! Crazier, Spicier and…Bouncier! Sling carapaces of 7 Luchadores to knock all... | Read more »
Raby (Games)
Raby 1.0.3 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.3 (iTunes) Description: ***WARNING - Raby runs on: iPhone 5, iPhone 5C, iPhone 5S, iPhone 6, iPhone 6 Plus, iPad Mini Retina, iPad Mini 3, iPad 4, iPad Air,... | Read more »
Oddworld: Stranger's Wrath (Games)
Oddworld: Stranger's Wrath 1.0 Device: iOS Universal Category: Games Price: $5.99, Version: 1.0 (iTunes) Description: ** PLEASE NOTE: Oddworld Stranger's Wrath requires at least an iPhone 4S, iPad 2, iPad Mini or iPod Touch 5th gen... | Read more »
Bounce On Back (Games)
Bounce On Back 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »
Dwelp (Games)
Dwelp 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: === 50% off for a limited time, to celebrate release === Dwelp is an elegant little puzzler with a brand new game mechanic. To complete a... | Read more »
Make Way for Fat Chicken, from the Maker...
Make Way for Fat Chicken, from the Makers of Scrap Squad Posted by Jessica Fisher on November 26th, 2014 [ permalink ] Relevant Games has announced they will be releasing their reverse tower defense game, | Read more »
Tripnary Review
Tripnary Review By Jennifer Allen on November 26th, 2014 Our Rating: :: TRAVEL BUCKET LISTiPhone App - Designed for the iPhone, compatible with the iPad Want to create a travel bucket list? Tripnary is a fun way to do exactly that... | Read more »
Ossian Studios’ RPG, The Shadow Sun, is...
Ossian Studios’ RPG, The Shadow Sun, is Now Available for $4.99 Posted by Jessica Fisher on November 26th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Mmmm, Tasty – Having the Angry Birds for...
The very first Angry Birds debuted on iOS back in 2009. When you sit back and tally up the number of Angry Birds games out there and the impact they’ve had on pop culture as a whole, you just need to ask yourself: “How would the birds taste... | Read more »
Rescue Quest Review
Rescue Quest Review By Jennifer Allen on November 26th, 2014 Our Rating: :: PATH BASED MATCH-3Universal App - Designed for iPhone and iPad Guide a wizard to safety by matching gems. Rescue Quest might not be an entirely original... | Read more »

Price Scanner via MacPrices.net

Black Friday: 15% off iTunes Gift Cards
Staples is offering 15% off $50 and $100 iTunes Gift Cards on their online store as part of their Black Friday sale. Click here for more information. Shipping is free. Best Buy is offering $100... Read more
BEVL Releases Dock Tailored for iPhone 6 and...
Seattle based BEVL has released their first product: an iPhone dock that is divergent in build quality, rock-solid function and visual simplicity to complement the iPhone. BEVL is now accepting... Read more
Black Friday: $150 off 13-inch Retina MacBook...
 Best Buy has 13-inch 2.6GHz Retina MacBook Pros on sale for $150 off MSRP on their online store as part of their Black Friday sale. Choose free shipping or free local store pickup (if available).... Read more
Black Friday: $300 off 15-inch Retina MacBook...
 B&H Photo has the new 2014 15″ Retina MacBook Pros on sale for $300 off MSRP as part of their Black Friday sale. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina... Read more
Black Friday: Up to $140 off MacBook Airs, fr...
 B&H Photo has 2014 MacBook Airs on sale for up to $140 off MSRP as part of their Black Friday sale. Shipping is free, and B&H charges NY sales tax only: - 11″ 128GB MacBook Air: $799 $100... Read more
Black Friday: 13-inch 2.5GHz MacBook Pro on s...
 Best Buy has the 13″ 2.5GHz MacBook Pro on sale for $899.99 on their online store as part of their Black Friday sale. Choose free shipping or free instant local store pickup (if available). Their... Read more
Black Friday: 21-inch 1.4GHz iMac on sale for...
 Best Buy has the 21″ 1.4GHz iMac on sale for $899.99 on their online store as part of their Black Friday sale. Their price is $200 off MSRP. Choose free shipping or free local store pick up. Price... Read more
Black Friday iPad Air 2 sale prices, $100 off...
 Best Buy has iPad Air 2s on sale for $100 off MSRP on their online store for Black Friday. Choose free shipping or free local store pickup (if available). Sale prices available for online orders... Read more
2014 1.4GHz Mac mini on sale for $449, save $...
 B&H Photo has the new 1.4GHz Mac mini on sale for $449.99 including free shipping plus NY tax only. Their price is $50 off MSRP, and it’s the lowest price available for this new model. Adorama... Read more
Early Black Friday pricing on 27-inch 5K iMac...
 B&H Photo continues to offer Black Friday sale prices on the 27″ 3.5GHz 5K iMac, in stock today and on sale for $2299 including free shipping plus NY sales tax only. Their price is $200 off MSRP... Read more

Jobs Board

*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Senior Event Manager, *Apple* Retail Market...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global event strategy. Delivering an overarching brand story; in-store, Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.