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Jaguar 64 FAQ - Part 4
Created and maintained by Robert Jung

All you need to know about the Atari Jaguar and more... (not for the faint hearted! - Ed) MyAtari presents the final instalment of the Jaguar 64 FAQ by Robert Jung.


I want something better than RF output from my Jaguar. What do I do?


Atari had an S-Video cable and a Composite video cable available for use with the Jaguar. See the "Peripherals" section for details.

If you are willing to build your own, the schematics for the expansion port are as follows:

Schematic #1

For Jaguar owners who wish to use SCART, a Jaguar-to-SCART RGB cable can be made as follows:

Schematic #2


How did the ComLynx port on the Jaguar work? Could I connect my Lynx to it?


The Jaguar does not have a ComLynx port per se, but has a ComLynx signal on the system bus. An expansion port add-on would have made the port available, and developers had announced plans for such accessories. It is possible to daisy-chain multiple Jaguars for multiplayer games into a "Jaguar network". In theory, it would have also been possible to connect Jaguars and Lynxes, though no plans for cross-system software were ever finalized.

There was also talk that the Jaguar's ComLynx signal could allow Lynxes to be used as peripherals: software could have been developed to allow Lynxes to be part of a Jaguar game as "smart" controllers. Again, no actual plans were ever announced.

For enterprising engineers who wish to build a ComLynx cable for two Jaguars, the following schematics from are available. USE AT YOUR OWN RISK!

Schematic #3

Assembly Notes:
As shown, the only 3 wires needed for the cable are 2, 3 and 6 (Tx, Rx, and Ground). All of these wires are on the bottom connector, so that is a good indicater of which way the cable plugs in the Jaguar. Shielded and RF-Choked cables work best. Due to the nature of this connector, it will be hard to shield this cable completely.

If you cannot find a 12-contact IDE Card Edge Connector, a 10-contact version can be used. A quick one can be built with no soldering using JDR MicroDevices (Part# IDE10). This is made for ribbon cable, but you can use regular shielded cables with a little work. As long as lines 2, 3, and 6 remain properly connected, there should be no difference.

Usage tips:

  • DO NOT PLUG THIS CABLE IN UPSIDE-DOWN! You may damage internal components if you plug it incorrectly.
  • TURN OFF BOTH JAGUARS BEFORE CONNECTING. You may damage internal components if you do not.
  • Since there isn't much strengh in the wires, remove the cable by the connectors.


Agh! My Jaguar is broken! How can I fix it?


Unfortunately, with the dissolution of Atari Corp., repair or replacement of broken Jaguars is no longer available; Atari/JTS does not have any units remaining for sale or replacement. On the other hand, with the low price of clearance Jaguars today, it isn't expensive to buy a new unit. In Great Britain, Telegames UK will offer to repair your Jaguar for a fee. They can be reached at:

Kilby Bridge, Wigston,
Leicester LE18 3TE, UK
Tel. +44-116-2880445
Fax. +44-116-2813437


Where can I get other information about the Jaguar?



  • Instant Replay Newsletter devoted to the Jaguar, with 7570 South Manor Avenue news and reviews. Write to Frank Eva Oak Creek, WI 53154 for more information.
  • Wild Cat A one-man, home-made Atari video gaming Phil Patton "fanzine." Subscvriptions are $12/year 131 Dake Ave. for eight issues, at 12 pages each Santa Cruz, CA 95062 issue. Covers all Atari consoles and computers.

Internet/USENET newsgroups and services:


USENET newsgroup. Contains news for all Atari video-game systems.

World-Wide Web Pages:

Go Atari is a web site that sells Atari software and hardware:

Telegames UK sells Jaguar consoles, games, accessories:

The Electric Escape is the official home of the Jaguar FAQ.

Jaguar Explorer On-line is a free electronic newsletter covering the latest news on the Jaguar (and other Atari-related matters):

Atarinews: On the Prowl is an electronic newsletter that reports the newest developments in the Atari gaming community:

The Jaguar Community Webring is a collection of web sites devoted to all aspects of the Jaguar:

Carl Forhan's (Songbird Productions) numerous Lynx and Jaguar projects can be found at:

The Jaguar Development Club and Jaguar City have joined forces to create a German/English web site for developers and enthusiasts.

The Atari Lynx and Jaguar Club Deutschland is on the web:

General-purpose Atari/Jaguar Web pages:

Also, Yahoo!'s list of Atari Jaguar web sites can be found at:

Llamasoft has a web page which contains updates on upcoming Jaguar projects, as well as ruminations on lovely llamas, hot music CDs, and other musings from Jeff Minter:

Mailing list:

  • Atari Jag-mail J. Sinn runs a Jaguar e-mail newsletter. For subscription information, write to


  • CATScan
    (209) 239-1552, 300/1200/2400/9600/14400 bps. Single line.

    The BBS is completely dedicated to Atari products and Atari video game consoles. Includes screen shots, press releases, pictures, and other files. Run by Don Thomas of Atari Corp.
  • Video Game Information Service.
    (201) 509-7324, 300/1200/2400/9600/14400 bps. Multiple lines

    Located in West Orange, New Jersy (USA). The BBS is completely dedicated to video gaming, and maintains files of cheats and reviews for all game systems. Carries video-game-related conferences from other computer networks, including Fidonet, Worldnet, and Globalnet.

On-line services:

  • America On-Line
    The PC Games/Video Games discussion group has areas devoted to the Atari Lynx and the Atari Jaguar consoles. Use the keyword PC GAMES, then go to the Video Games discussion board. From there, select Atari Discussion, then the console of your choice.
  • GEnie
    A dedicated/expanded Jaguar roundtable has been established. Type M475;1 to reach it. For assistance regarding the roundtable, send e-mail to JAGUAR$ on GEnie.


How was development for the Jaguar done?


Jaguar game development environments existed for the Atari TT030 computer or an IBM PC/compatible. Art development could be performed on any machine, whether a low-end Apple Macintosh or commercial rendering software such as SoftImage. Wavefront's "GameWare" was the official 2D/3D graphics development system; Atari itself used GameWare for in-company development, and registered third-party Jaguar developers could buy GameWare licenses at special discount prices.

Estimated price for a developer's package was $9,000 for the TT030 setup, and $7,500 for the PC/compatible platform. The package included a Jaguar development unit, documentation, and development/debugging software. The Jaguar had modified boot firmware to run the development board (the "Alpine board"), and it had a cable coming out to provide signals to the Alpine board that are not normally present via the cartridge connector.

CD-ROM development packages (including the cartridge development kit) were ranged at about $8,000, and were upgradeable from the card-only kit.

Software routines packaged with the system included a multi-channel polyphonic FM/Wavetable synth; JPEG decompression; video set-up; drawing primitives; 3D rendering with gourad shading, texture mapping, and camera manipulation. GCC is the primary 68000 C compiler; support for other languages was not available from Atari, but developers were free to use whatever tools they may prefer. The development toolkit ran under DOS, TOS, or Linux. Work was proceeding on a Linux development system using the GNU tools.

The centerpiece of the TT030 development platform was DB, an assembly- language level debugging tool. The Jaguar and the TT030 were connected with a parallel cable, and software could be debugged interactively without interfering with the Jaguar's screen display. DB supported the use of scripts and aliases, which simplified the use of complex or common functions.

Support for the development packages was primarily provided by Brainstorm (Atari France), who worked closely with Atari Corp.

Atari granted final code approval, but did not see the need to "censor" games. Every game was given one man-month of compatibility and quality testing before it was approved. Atari offered technical support via FAX, mail, electronic mail and voice. Atari allowed developers to source their own cartridges, documentation and shells if desired. Jaguar software is encrypted with a proprietary key, thus preventing unauthorized developers from releasing Jaguar software.

Cross Products (SNASM) offered an alternative Jaguar Development system. It came with a multi-windowed debugger, assemblers, compilers, and SCSI support, for approximately $3,700. The package allowed for full screen, source level debugging of multiple processors, in C or assembler. This was software only for the IBM PC; the Jaguar development hardware (Alpine board, modified Jaguar, etc.) had to be purchased separately from Atari.

Ambitious hobbists have started their own unendorsed Jaguar development efforts, with several "home-brewed" development systems and electronic documentation of the Jaguar's inner workings. Several games have been written for play on the "Jaguar Server" development system (requires some hardware modification to an existing Jaguar, and an IBM PC or Atari ST computer).

Information about these efforts may be found on the web at the following sites:

In addition, the Jaguar Development Club of Germany has made the official Jaguar development manual available exclusively for downloading on their home page (


Where is the encryption key for Jaguar games? Now that Hasbro has declared the Jaguar an "open system", the key should be available to the public, right?


Wrong. Even though Hasbro has officially declared the Jaguar to be an "open" system, they have not released the encryption code for Jaguar games because they do not know what (or where) it is. Hasbro's declaration of openness on the Jaguar simply means that developers and hackers are free to use any means they can to develop and sell Jaguar games -- whether they do this by figuring out the encryption key, bypassing the Jaguar's startup checks, or using any other techniques, Hasbro's lawyers will not bother anyone along the way.

As of this writing, the unofficial word in the Jaguar community is that the few people who DO have access to the Jaguar's encryption key are trying to make sure that they're "safe" -- that if they release the keys, they won't be prosecuted by some other company for some other reason.

But all hope is not lost! According to Scott LeGrand of 4Play, former Atari engineer Dave Staugas has mentioned that the Jaguar's startup encryption check has a "back door" in the software -- a safety measure to be used in case the "real" encryption key was lost. Investigation in this direction is currently continuing, and the latest (unconfirmed) theory is that the encryption (and the back door) works as follows:

  1. A 512-bit key is applied to the memory data, and then a 32-bit checksum is used for validation.
  2. The bottom 8K or so of ROM memory is filled with a key generated from the cartridge data. When a Jaguar boots, this 8K of data is combined with the ROM data to generate the 32-bit checksum.
  3. If the checksum is valid, the cartridge is allowed to run.
  4. The "back door" checksum value is: 03D0 DEAD (hex). And yes, it IS a cheeky reference to the Jaguar's then-current competitor... More details about the Jaguar encryption process will be added as it becomes publicly available.


Since the Jaguar encryption code is missing, does that mean there's no way for people to write their own Jaguar games? Is the whole "open system" thing a crock?


Not at all! Hobbists and developers have been writing their own Jaguar games for a while now; the lack of an encryption key simply means they can't distribute the game to non-developers.

But wait! In response to this need comes JUGS, the Jaguar Unmodified Game Server. JUGS is a computer hardware/software package that allows you to download Jaguar games from your personal computer to a Jaguar and then run them. With dozens of homebrewed Jaguar programs in existence, this opens up a new source of software for the Jaguar enthusiast.

To use JUGS, you need the following:

  • A copy of the game BattleSphere.
  • An IBM-compatible PC with a RS-232 communications port.
  • A JagLink interface. For more information about JUGS, ordering information, and available developer titles, visit

Electric Escape logo
Last update: 4th December 2000 

This file is not maintained by, overseen by, endorsed, or otherwise associated with Atari Corp., JTS, or any of its subsidiaries. It's just a collection of questions and answers, with a few news tidbits thrown in. Robert tries to get the latest news and information into this FAQ; however,he's only human, and might miss something important due to real-life demands.

The latest version of this FAQ is available here. Send corrections, news, updates, comments, questions or other stuff to

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MyAtari magazine - Feature #4, April 2001

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