Learning about Radio Shack Printers

[MHaensel]

Everyone needs something to do during the shutdown. While researching TRS-80 printers in Radio Shack computer catalogs and 80 Micro magazine, I've found some interesting things:

 

The Line Printer I was . . . limited. It printed upper-case characters and numbers only, monospaced, no block graphics, no bitmap printing. It also used 360 watts of power!

 

Fortunately, things improved quickly. The Line Printer II/III added lower-case characters. The IV/V/VI added added block graphics characters. The IV and VI also added proportional printing, although the V stayed monospace in the interest of speed. 

 

But it wasn't until the Line Printer VIII that TRS offered a fully-capable dot matrix printer, with dot-addressable graphics, a full TRS-80 character set, and proportional printing. For $800 in 1982, it wasn't too bad a deal.

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The beefier printers put the *heavy* in heavy duty.

Line printer I: 45 pounds
Line printer V: 42 pounds
DMP-500: 50 pounds
DMP-2100: 42 pounds
LMP-2150: 60 pounds  - although this printed a full line at a time, so it's closer to mainframe hardware than a microcomputer printer

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The Daisy Wheel printers had high-quality output. The original Daisy Wheel II was rated for 43 cps! But it also made an awful racket while printing:

Later daisy wheels got oddly slow. The DWP-510 and DWP-520 kept up with the original, but others were about half as fast. And speed doesn't correlate with price or release date! You could but a $1500 slow printer or a $1000 fast printer.

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If someone has better info than me, I welcome corrections. What other neat stuff is there to know about these printers?

[jhd]

The Line Printers were a bit before my time. 

 

I owned a DMP 100 -- the low-end dot matrix printer. The exact same model (with a different interface and ROM) was sold as the Gorilla Banana for the Commodore series and very possibly other names: http://mrweese.blogspot.com/2007/06/gorilla-banana.html

 

It was slow, noisy, and the print quality was really poor. Most notably, there were no lowercase descenders -- everything was crammed into one line. I mostly used it for program listings and some graphics; it was unsuitable for printing schoolwork.

 

 

[Michael Kline]

21 hours ago, jhd said:

The Line Printers were a bit before my time. 

 

I owned a DMP 100 -- the low-end dot matrix printer. The exact same model (with a different interface and ROM) was sold as the Gorilla Banana for the Commodore series and very possibly other names: http://mrweese.blogspot.com/2007/06/gorilla-banana.html

 

It was slow, noisy, and the print quality was really poor. Most notably, there were no lowercase descenders -- everything was crammed into one line. I mostly used it for program listings and some graphics; it was unsuitable for printing schoolwork.

 

 

Yeah, I agree.

 

My first DMP was the DMP-100. It was a Christmas present. I never liked the printer. Unidirectional, loud and slow. Even the standard font it used was weird. Later, I upgraded to the DMP-130A. I've been happy ever since. At one time, I did own a DMP-420. It was a beast, and it was a great printer.

[Turbo-Torch]

My first printer was the DMP-110.  I saved forever and bought it when it was on sale for $299.00.  It was a love/hate thing from day one.

It had buffer memory, boasted some sort of dual hammer print head and promised the world with hi-res graphics, high quality word processor mode, many print densities, insanely small micro-font and even cursive.  The printer itself looked incredibly cool...aerodynamic, light beige with a smoke tinted cover.  Quite possibly the best looking printer ever made.

 

Reality was the print quality did not live up to the hype.  I took it back under warranty a few times, they made adjustments and eventually told me that's as good as an inexpensive printer gets.  I will say it did deliver on all the features.  Mirco-font was cool, you practically need a magnifying glass to read it. 

 

In high school, they started giving us fancy computer generated report cards with multiple fonts and line graphics.  I was able to mimic it using Scripsit on my Model III and made some new report cards with improved grades for two close friends who would have otherwise had their asses kicked and been grounded.  Instead of keeping it a secret, word got out quick.  I made and saved a template which allowed me to make a new card in about 5 minutes with teachers' names, room #s, previous grades and the new requested grades.  They were really spot on good.  I was only charging $10 for a new card but would bring in between $300 to $400 during each report card week.  On report card day, my street looked like April 15th at a tax preparers office. lol

 

Following year, another kid decided to muscle in on my business and his cards looked like absolute shit. Dude got busted and suspended for a week!   The school started using a notary type stamp and alerted parents to look for it.  That scared the hell out of me and I was done.  And all the way to graduation, I thought it might come back to bite me, but it never did.

Till today I wonder what happened when some of those kids tried to get into college and their transcripts didn't come close to matching up with what they brought home to mom and dad. 

 

So yeah, that printer has some fond memories attached to it and I still have it.  Ribbons are very rare and it shares them with one obscure Commodore printer.  I have quite a few new sealed ribbons, which of course are all dried out, but are easy to re-ink with a roll-on bottle thing from Staples.

 

Several years ago I picked up a spare Model III on Craigslist for $25.  The guy also gave me a DMP-100 with it and a ton of fan-fold paper.  The computer and printer looked like they'd never been used and work great.  The 100 actually has better print quality than the 110 imo.  I also like that it's battleship gray and matches the Model III.

[sn0211]

I just recently bought a Tandy DWP230 and I'm finding it difficult to get wheels. Will the TA wheel work on my machine?

[Green3]

On 11/24/2020 at 3:44 PM, MHaensel said:

What other neat stuff is there to know about these printers?

1. Here's a good list.

 

2. All but one of the Tandy/Radio Shack printers had an industry-standard Centronics Parallel port enabling it to be used with just about any computer of the era. 

 

3. A limited sub-set of them also had a four-pin DIN serial port enabling them to also be used by the Color Computer (and the short-lived Micro Color Computer, also known as the MC-10).  They're listed here.  

 

4. The sole exception to point 2 above was the Radio Shack TRS-80 TP-10, an ultra-cheap ($99) thermal printer (hence "TP") that only had a CoCo-style serial port and used thermal paper only half as wide as regular paper.

 

5. Radio Shack printers were often re-branded printers from other manufacturers, produced under license with Tandy-specific ROMs.  Or they at least used a central mechanism used by others.  No shame in that; the practice was ubiquitous in the industry.  For example, the CGP-115 color plotter (marketed by Radio Shack as a "printer") used the widespread ALPS DPG-1302 mechanism, used by a bewilderingly long series of other prominent computer brands, including Atari, Canon, Commodore, Texas Instruments, and many others.  Similarly, the CGP-220 (like the IBM Colorjet) was simply a Canon PJ-1080A.

 

6. The Commodore 64's 1541 floppy disk drives were well-known for having the same microchip in them that the C64 computer itself did, enabling it to carry out complex instructions.  What's less well-known is that the CGP-220 had the same Motorola 6809 CPU as the Color Computer itself, and the same 4K of RAM that the original CoCo came with.  Maybe somebody could hack one enough to make it be a full-fledged CoCo?

 

 

Edited March 1 by Green3

[Michael Kline]

8 hours ago, Green3 said:

1. Here's a good list.

 

2. All but one of the Tandy/Radio Shack printers had an industry-standard Centronics Parallel port enabling it to be used with just about any computer of the era. 

 

3. A limited sub-set of them also had a four-pin DIN serial port enabling them to also be used by the Color Computer (and the short-lived Micro Color Computer, also known as the MC-10).  They're listed here.  

 

4. The sole exception to point 2 above was the Radio Shack TRS-80 TP-10, an ultra-cheap ($99) thermal printer (hence "TP") that only had a CoCo-style serial port and used thermal paper only half as wide as regular paper.

 

5. Radio Shack printers were often re-branded printers from other manufacturers, produced under license with Tandy-specific ROMs.  Or they at least used a central mechanism used by others.  No shame in that; the practice was ubiquitous in the industry.  For example, the CGP-115 color plotter (marketed by Radio Shack as a "printer") used the widespread ALPS DPG-1302 mechanism, used by a bewilderingly long series of other prominent computer brands, including Atari, Canon, Commodore, Texas Instruments, and many others.  Similarly, the CGP-220 (like the IBM Colorjet) was simply a Canon PJ-1080A.

 

6. The Commodore 64's 1541 floppy disk drives were well-known for having the same microchip in them that the C64 computer itself did, enabling it to carry out complex instructions.  What's less well-known is that the CGP-220 had the same Motorola 6809 CPU as the Color Computer itself, and the same 4K of RAM that the original CoCo came with.  Maybe somebody could hack one enough to make it be a full-fledged CoCo?

 

 

Cool! I used to have the CGP-220. It had the serial port and I used it for my CoCo. I wish I still had it. I didn't know that it was manufactured by Canon.

[cwilkson]

I have a DMP132?  I think it's a 132.  It was a GREAT printer!  It had both parallel and serial ports.  I used it with my Coco 2 in high school and briefly in college.

But I haven't used it for 30 years.  I need to just sell it.

 

I remember having a program to do graphics screen dumps.  It took forever to dump a PMODE 4 image.  But it was really cool.

I wrote my own basic program that was much faster.  IIRC it could dump the screen to paper in about 1 minute.

 

I always wanted to go back and see if ASM could speed it up.  But I think the print head was the limitation.  Or maybe it was the baud rate.

I think it was limited to 1200 or 2400 baud over serial.