1981 SIO Modem

[ClausB]

As a senior in the MSU Computer Science program I had terminal privileges on the Cyber mainframe. Woohoo, no more punched cards! Problem was, the terminals were usually all taken during the day and evening, and late night was a poor option since I lived three miles from campus in a low-rent area and the busses stopped running at night. If only I could connect from home with my shiny new Atari 400! But modems cost $200 and the 850 interface even more.

 

Ciarcia's Circuit Cellar in BYTE magazine came to the rescue. The August 1980 issue promised an RS-232 acoustic modem for $50. But the 400 had no RS-232 port. The SIO port could do the protocol but not the voltage levels. Well, Ciarcia kindly wrote how to drive his modem with TTL signals, and my first real electronics project was born.

 

I ordered the kit from Micro-Mint, plus speaker, mic, and power supply. The owner of New Dimensions in Computing taught me how to solder. He was an Atari dealer and repair shop, so I asked him to order an SIO cable which I would cut, but he went one better and got me an SIO connector. Nice!

 

I built and tested it, programmed the SIO port for 300 baud, and wrote a simple 40-column terminal program. I got the number from my professor, dialed in to the Cyber, and did my homework without trudging through the snow. Cool! My housemate loved to call friends in the evening, so I often had to work late at night anyway, although warm and safe.

 

The Cyber's 80-column output got hard to read in 40 columns, so I wrote an 80-column terminal program for GR. 8 mode, and it was surprisingly legible on my B&W TV. That eventually became DT-80 and ACE-80, as I've posted before.

 

Here's the finished product. The switch is for selecting TTL or RS-232.

 

[+Larry]

Interesting story! ACE-80 is still the best software 80-column solution I've ever seen for the A8. It is dynamite on my All-in-Wonder PC/Atari display.

 

Just curious -- did you ever try to make an internal version so that it didn't take the cartridge port, or maybe PBI?

 

-Larry

[ClausB]

Thank you, Larry. No, I suppose the right cart version for the 800 was the closest we got to that.

[ClausB]

Here's the BYTE issue, thanks to ThumpNugget.

http://atariage.com/forums/topic/167235-byte-magazine/?do=findComment&comment=2067352

 

Interesting ad on the last page of the article, from OSS, showing versions of Atari BASIC, OS/A+, and Assembler / Editor for the Apple.

 

 

CCC Modem from BYTE Vol 05-08.pdf

[Ransom]

That's really cool. Thanks for sharing the story and pictures.

[ClausB]

Here are the terminal programs. MODEM.SRC.txt is the 40-column terminal and DUMB.SRC.txt is the 80.

 

[_The Doctor__]

Awesome,

 

This is the kind of thing that makes it all worth while. You have inspired me and I will be relying heavily on the community shortly to sort thru a major gift (imho) a friend bestowed apon me to lift my spirits... it is an office full of code, source, artwork and equipment that needs restoration, the programmer/partner gave his blessings and old bussiness cards. This company worked on projects for many computers systems for diverse company client base including Atari. In fact rights for most of the 800 based stuff was given freely as the clients were mainly interested in cashing in on the 2600! Go figure rights held on the 2600 and given on the computer stuff!

 

Claus I may need to rely on your hardware eye to help me out on some of it, or to direct me to who will know what to do...

 

We have a ramrod board that is misconfigured and need a cheat sheet to set it up, it has two sets of eproms installed,

 

We have a rom simulator that will need lots of love to get going and configure... The fellow say he could update the roms while they were running on the Atari and see the updates in real time? Sometimes it would crash due to simultaneous access but most of the time is was just fine? The power supply seems to be based on capacitors and a transformer... these are humungous it's insane! If it's not complete your the man to help design the missing pieces.

 

It appears to be cpm based..8 inch disk drives... and full form factor hard drive... so heavy... needed help to move them carefully.

I could go on and on but it is best to take it a step at a time.

Edited April 10, 2014 by _The Doctor__

[ClausB]

Thanks.

 

That ROM simulator sounds cool. Which company used that?

[_The Doctor__]

It is office number 0012 of Roklan Corp.

Much is incomplete... I have resurrected almost all of the hardware but we are missing certain cords/ connections and literature to make it all come together. I have contact with one of partner/programmers from Roklan and have been told what took such a wonderful and growing company down. An outside contract with a cartridge pcb maker/supplier forced them to liquidate. I have sources, rom images, and different versions of projects for the 2600, 5200, 800, XL, VCS, C64, CP/M, TI94, TRS, Apple and Intellevision systems.

Did I miss someone?

It would seem they worked on most of it on the cp/m slash Atari system and then cross compiled it all, then would fix tweak or modify it on the specific system to get the bugs out. There are disk versions/ then rom versions then final versions, then production protected versions. I also found out that not everyone is listed correctly on final products, sometimes they list the wrong programmer for the game... in fact the wrong programmer is in the credits on the game and literature that went into production. I guess it wasn't a big deal back then. So long as you got paid. This is quite and educational journey.

[_The Doctor__]

Maybe this belongs in another thread and all of it should be moved there... but I just feel it is the same sort of thing. Some inventive wonderful stuff that needs to be preserved and documented. Without people like you the computer industry never would have made it.

[_The Doctor__]

Roklan source says you modify the memory on the cp/m machine and it appears in the rom of the atari....like they are sharing the memory banks... between the two at the same time....to the cp/m it's ram to the Atari it's rom...

Just be aware of the bank structure in ram.....

[+Stephen]

Here are the terminal programs. MODEM.SRC.txt is the 40-column terminal and DUMB.SRC.txt is the 80.

 

Sorry to necro-bump this, but IO was reminded of the thread by another one here. Just wanted to say thanks for the source code, and you code like my brother (not a single comment)

[ClausB]

I used to be sharp enough to code without comments, at least on small jobs. By the time that grew into ACE80 though, I did need to add some comments.

[ClausB]

Then there's the other extreme, stupid comments like:

LDA #8 ; Put an 8 into A

 

Over-commenting can make bugs harder to find, as you tend to read the comments and believe that's what the code does, instead of reading the code to see what it really does.

[+Nezgar]

Claus, if you made some new ACE80 Carts, you could make quite a few bucks apparently. Maybe sign them too to make them extra rare.

 

https://www.ebay.com/itm/123371839945

[+MrFish]

Claus, if you made some new ACE80 Carts, you could make quite a few bucks apparently. Maybe sign them too to make them extra rare.

 

Sorry... it's doesn't work that way. New carts get new cart prices.

 

You can add to the that, "for sale prices don't equal sold for prices".

 

[Edit] ...especially when it says, "Make Offer".

 

On the other hand, it is a pretty rare cart.

Edited December 7, 2018 by MrFish

[ClausB]

Member Larry made a flash cart version some years ago. Search for it.

[+Nezgar]

It was just an amuzing thought if the original authors made new ones if only to dilute the high ebay price/ for fun. Noone can claim the new one is unauthorized / not authentic.

 

It's rare for authors of the products of the day to still be active in the communuty. I just think it's so cool that Claus is still active here.

 

Never seen the ACE80 in person, I'll take a look, thanks for the lead.