Classic Computer Magazine Archive CREATIVE COMPUTING VOL. 9, NO. 6 / JUNE 1983 / PAGE 133

Praxis makes perfect; Olivetti Praxis Typewriter conversions: are they worth it? Gordon McComb.

Praxis Makes Perfect

Olivetti Praxis Typewriter Conversions: Are They Worth It?

Printers can be so dull. I dreaded the thought of having to buy a daisywheel machine, but the chore had become inevitable. Midway through my search, I entered a neighborhood computer store, and gazed down one of the carpeted isles.


The models sat listlessly, perched atop an imitation wood counter--in an unending line--clones of clones of clones. I had looked at so many that after a time, their images began to blur into one congealed, sticky mess. They all seemed to work the same, look the same, cost the same. That is, all except one--one that I had never seen before. In reality, it wasn't hard to single this new one out from the crowd.

A lamp shone above the printer--the unique one--and cast a warm glow over its classic black exterior. I read the writing emblazoned on its sleek body-- Olivetti Praxis 30. "But that's a typewriter,' I said to the salesperson. "It's also a printer,' she gaily replied. She smiled, reached behind the printer, and turned it on.

"So it is,' I mused, tracing a thick pale blue cable that emerged from the base of the printer. The cable was attached to a small plastic box that rested innocently beside an Osborne portable. Another cable twisted and looped between the RS-232 port of the computer and the box.

I threaded a sheet of letterhead into the printer and rolled the platen until the tip of the paper peeked past the printhead. I told the computer to print and glanced over at the Olivetti.

The daisywheel printhead slid effortlessly to the left margin. The platen advanced a few lines with a strange "shick shick' sound, and the printing began.

It wasn't the speed with which the letters were printed that impressed me. In fact, the Olivetti typewriter/printer has a top speed of only 12 characters per second. Rather, it was the superb type quality that caught my eye, and the fact that for less than $800, I could get not only an interchangeable daisywheel letter quality printer, but a full featured electronic typewriter as well. Double duty for half the price! It wasn't hard for me to decide which printer I was going to buy.

But as I was signing my check, I over-head another customer ask how different this Olivetti typewriter/printer was from the other Praxis-based model that was out. "What other model!?' I shouted as I stashed the check back in my coat pocket. "You mean there's another one?'

Yes. What I found out was this: Several companies offer converted Olivetti Praxis 30 printers, and at first glance, it would seem that since they all use the same basic typewriter, they too, would be the same. Look again. The two most popular Praxis conversions--the Bytewriter and the Olive-80--are far from being similar. Here's what I found out about both machines.

What's a Praxis?

A description of the Olive (which is available in both typewriter/printer and typewriter conversion kit models) and the Bytewriter wouldn't be complete without first telling you about the Olivetti Praxis 30, the machine upon which both printers are based.

The Praxis is a fully portable typewriter --it even comes with its own rigid plastic carrying case. The real key to the Praxis is that it is electronic; that is, there are no linkages or solenoids or bellcranks activated when you depress one of the keys as there are with an IBM Selectric or standard electric typewriter. The Praxis keyboard is engineered like a computer keyboard; it is just a series of switches.

When one of the keys is depressed, an encoder circuit inside the typewriter notes which key has been struck, and directs the motor driven printhead to type the proper character. A second motor is used on the typewriter to position the printhead along the length of the platen.

The Praxis uses daisywheel elements, so you can switch from one typestyle to another. The wheels aren't compatible with any other printer or typewriter, so you have to buy them specially for the machine. The resin-tipped plastic wheels retail for $29.95, but there are more than a dozen different styles available (resintipped wheels are supposed to last longer than plain plastic ones). The Praxis uses cartridge loaded fabric and film ribbons.

The Praxis has its own 12-character keyboard buffer, and it is extremely difficult to out-run it. You cannot jam keys. It also remembers the last ten characters typed. So if you make a mistake, you can go back to the letter (as long as it is less than ten characters from where you left off), hit the "correct' key, and the character will be automatically lifted off by the correcting ribbon built into the machine.

Although the Praxis doesn't print all 96 characters normally found on a standard daisywheel printer, it is capable of producing some special purpose characters such as , N, , and [o. Separate keys don't exist for these characters; a switch on the typewriter labelled KB I/KB II allows you to toggle between two keyboards, and print the special characters.

Even though the Praxis typewriter doesn't allow you to alter the printing pitch (from 12 characters per inch to 10, for example), it is internally capable of multi-pitch operation. Both the Olive and Bytewriter take advantage of this fact and add control over pitch, allowing you to use 10, 12, and 15 characters per inch wheels. (Another Olivetti model, the Praxis 35, is also available--the only real difference between the 30 and 35 is that the latter has an external switch that offers the typist pitch control. Olivetti gets about $100 more for the 35 for what amounts to a 90c switch; it hardly seems worth it.)

Other features of the Praxis include single, space and a half, and double spacing, electronic tab and margins (no mechanical stops here), warning buzzer, and a "relocate' key that automatically returns the head to the last print position --a time saver when you stop typing and go back to correct a letter or word at the other end of the line.

The Printers: A Close Look

So much for the typewriter itself. What about the printers? There are three primary differences:

Perhaps the biggest difference between the two printers is that the Bytewriter is a parallel machine and the Olive is a serial machine. The two are not available in different versions. This can limit your choices depending on what port your computer has.

My Osborne, for instance, has both a serial and a parallel port. Both are unused, so my choice of printer isn't restricted. You, on the other hand, may have only one or the other port. If you have, say, an Apple, you might already have a serial card for a modem or a dot matrix printer. Unless you want to spend another $100 for a parallel card, you will probably opt for the Olive. Even if you have both ports, your choice may be limited if one is used exclusively for a particular peripheral. In any case, this is up to you to decide.


Another primary difference is that the electronics for the Olive are all out-board: everything is packed in a small plastic interface box. A ribbon cable joins the box to the keyboard output terminals inside the typewriter. You can disconnect the interface box from all its cables if you ever need to transport the printer, but you will have one more thing to carry, of course. By the way, the separate interface box is normally powered by a separate power supply like the one on your calculator that plugs into the wall. The supply costs $9.95 extra.

The electronics for the Bytewriter are all internal. A small connector located on the righthand side of the Praxis allows you to snap on a specially made cable (about $35 from Bytewriter) from the printer to your computer. You can make the cable yourself, too--the instructions that come with the Bytewriter tell you which pins do what. Since everything is inside the machine, there is nothing else for you to carry if you are one to tote your computer system around with you. The Bytewriter electronics use juice from the Praxis power supply.

Printing Functions

The third major difference is that several of the Olive printing functions are software controlled, whereas the Bytewriter uses small DIP switches to control its functions.

Some cases in point: To alter the pitch selection on the Bytewriter, you depress one of three switches, all of which are located on the exposed side of the built-in electronics. A pencil makes the job easier because the fit where the electronics are mounted is tight.

The keyboard toggle (KB I/KB II) must be controlled manually with the Bytewriter. For example, to create a , it is necessary to type a shifted 2 (@ on my Osborne) on the computer. When printed out, the keyboard switch must be momentarily placed on KB II.

To prevent other, unwanted special characters from being printed, it is necessary to quickly switch back to KB I.

The Olive makes this a little easier. After you have patched the program, you simply leave the switch in KB II and use a software toggle. In WordStar it is control-PR. Hitting control-PR again cancels the command. The Olive also allows for manual pitch selection, but you must build a jumper switch to do it.


Lastly, when the Praxis is first turned on, the margins are set at 30 and 90 (for 10 pitch operation). You can change these margins if you wish, although your changes will be erased when you turn the machine off. Whether you use the default settings or your own, the Bytewriter prints within these margins. If your right margin is set at 90, you cannot print beyond that. If you attempt to print past the right margin, the Praxis will beep at you, and you will lose the rest of the characters in that line. The lesson here: When you use the Bytewriter, it is important that you move the right margin all the way over when using computer input to avoid this loss of text.

This isn't a problem with the Olive, because it resets the margins to 0 and 110 (far left and far right) immediately before it prints (your word processing program handles the margins). At the end of the printing session, the Olive restores the Praxis to its default margins of 30 to 90.


The top print speed for both the Bytewriter and the Olive is 12 characters per second (cps), which is the same as Smith-Corona's TP-1 printer, and just slightly slower than Brother's HR-1 printer. Isn't 12 cps slow? It can be if you are in a hurry. I have found that it takes about 2 to 2-1/2 minutes to print out a letter or a double-spaced manuscript page (that includes the time it takes for the printhead to return after each line--the Bytewriter and Olive are both uni-directional only). While the machine is doing its thing, I'm off raiding the refrigerator, checking the mail, making phone calls.

While it is possible to live with the 12 cps speed (once you get used to it), you will find that some printing jobs just aren't well suited for a converted Praxis. Even though the Praxis (typewriter) has a tab key, the Praxis (printer) single spaces to each tab stop. This goes for both the Olive and the Bytewriter. (Technically it is capable of a horizontal tab; but your software must initiate the HT command--after you have manually set the tabs--rather than simply a series of spaces, as with WordStar.)

So if you are doing a chart, a complicated outline, or some other document that has many indentations, you will find it takes time not only to print out the characters, but for the head to align itself at the next printing position. A simple chart with twenty items took me over five minutes to print, because the items were on the extreme right-hand side of the paper. After the printhead typed one word, it returned to the left margin, single spaced all the way out to the next word, typed it, and repeated the process.

Because the Praxis is a portable machine, it isn't meant for heavy duty use. If you think of it as a printer, it is easy to forget this and run the machine day and night. Don't do it! You'll end up with a smoking hunk of metal and plastic. Ideally, the Praxis should be used for fewer than 20 pages per day. Anything more could shorten its life considerably.

In Use

The operation of the Bytewriter is fairly straightforward. You simply plug it in to any Centronics-compatible port and you're off and running. The Bytewriter does allow you one custom adjustment. The unit always responds to a line feed (LF) command by returning the printhead (carriage) and advancing one line.

The Bytewriter can be made to respond to a carriage return (CR) command in two ways: it can return the printhead and advance one line, or it can simply return the printhead. Some computers issue both a CR and an LF command at the end of a line, resulting in double-spacing (even when the typewriter is in single-space mode). The Bytewriter allows you to override this by squelching the second linefeed. This one provision also makes it possible to return the printhead to the left margin to create underlined text.

The Olive provides the above feature, along with many more independent options. Most of these options are provided because the Olive uses the serial port, which by its nature, requires peripherals to be somewhat intelligent and fast on their feet.

For example, you can change between 110, 300, and 1200 baud (which, of course, is not necessary for a parallel printer). Handshaking, those signals that tell the Praxis and your computer what the other is doing, can be either software or hardware controlled. Software control uses the standard XON/XOFF protocol found in such printers as the Diablo 630 (so if you have software that can run with a Diablo serial printer it will probably work with the Olive without modification). When hardware handshaking is used, you can choose any of four RS-232 pins and various pin polarities. You can also power the Olive through the RS-232 cable, assuming of course that your RS-232 port has compatible engineering. All of this and more are controlled by switching a gang of jumpers inside the Olive control box.

While the Olive provides more flexibility than the Bytewriter, and is perfect for the user with a non-standard system, it can be more difficult to use for those with little or no technical background. Yes, the manufacturer will give you hints and suggestions on how to hook things up, but it is nice to be able to plug something in and have it work. If you are one who likes sheer simplicity, you should look into the Bytewriter.


It is not unusual for printers to have self-test features built in, and the Bytewriter and Olive are no exceptions. The Olive runs through a self-test-- prints out two lines of each character-- every time it is turned on or reset. This, admittedly, can be tiresome, so the Olive allows you to defeat this self-test.

The Bytewriter is a little different. It won't crank out a test each time it is turned on. You must hook up a jumper cable to evoke the self-test feature. The bad part? You must make the cable yourself.

The Bytewriter and the Olive are both capable of underlining. Both machines accomplish this by either backspacing, or returning the printhead and going back to the word to be underlined. With the Praxis, both ways seem to take about the same amount of time. The Olive is also capable of printing in bold face. Again, it performs this by either backspacing on each letter or doing a complete carriage return.

Ease of Use

Both the Bytewriter and Olive are easy to use, although there are some small complaints that should be covered. The Olive has a small reset key that is recessed into the front panel of the interface box. The hole is too small and the switch is set too far inside. Your pinky will probably be small enough to press it, but it doesn't provide a very positive feel.

The interface for the Olive comes out the front of the Praxis, then tucks underneath the machine and exits at the rear, where it continues on until it attaches to the interface box. And then of course, you have the cable between the computer and the box as well. What I found is that it is not hard to end up with a mess of cable on your desk. Although the Bytewriter doesn't have the extra length of cabling or an external box, the interface connector is located on the side of the machine, rather than the rear. Again, you can easily get lost in a thicket of cable.

If you buy a Bytewriter, you should know that Olivetti will still honor the original warranty, just as long as the fault lies within the typewriter. You can ship the machine back to Olivetti or take it to any one of dozens of regional authorized dealer repair depots. Bytewriter covers their portion of the contraption with a 90-day guarantee.

At this writing, the same doesn't go for the Olive, however. If you buy a facrory-converted Praxis, your only recourse for an in-warranty repair is to send it back to The Olive Branch (located in Hayward, CA). If you convert a Praxis yourself while it is still under warranty, you void that warranty, of course. This all can change, so contact Olive for the latest details before you make your decision.

A final word about instruction manuals. The Bytewriter, being fairly simple in set-up and operation, doesn't have much in the way of a manual--about seven or eight pages worth of text. There is no technical information provided other than the pin-out assignments for the connector.

The Olive, on the other hand, is replete with information--setup, use, and technical. It comes with charts and graphs showing character sets, specifications, a sample self-test program (in Basic), and more. If you already have a Praxis 30 or 35, you can buy just the interface board from Olive and do the conversion yourself (which requires that you solder a pair of ribbon cables inside the machine). The instructions are easy to follow.

For more information on the Bytewriter, contact Bytewriter, 125 Northview Rd., Ithaca, NY 14850, (607) 272-1132; for the Olive-80, write The Olive Branch Association, Ltd., 26291 Production Ave., Suite 205, Hayward, CA, 94545 (415) 887-5633.

Figure 1.

This is a sample printout (using a Courier 12 pitch wheel and film ribbon) from an Olive-80 printer, a converted Olivetti Praxis 30 typewriter. It is capable of underlining, as well as boldfacing. Printer features are controlled by software.

Figure 2.

This is a sample printout (using a Courier 12 pitch wheel and film ribbon) from an Olive-80 printer, a converted Olivetti Praxis 30 typewriter. It is capable of underlining, as well as boldfacing. Printer features are controlled by software.

Figure 3.

This is a sample printout (using a Courier 12 pitch wheel and film ribbon) from an Olive-80 printer, a converted Olivetti Praxis 30 typewriter. It is capable of underlining, as well as boldfacing. Printer features are controlled by software.

Table: Olive-80 Character Set.

Table: Praxis Printer/Typewriter Comparison Chart.

Photo: The Olive-80 and Olivetti Praxis 35 typewriter cum printer: it can be used as both any time.

Photo: The Olive-80 allows for user-selectable options (explained in text). Plastic covered jumpers are used in the changes.

Products: Bytewriter (typewriter)
Olive-80 (typewriter)