Taito G-Net System

Taito G-Net LogoThe Taito G-Net system was released in 1998 and is based on Sony PlayStation hardware. It’s a cartridge based system and uses PCMCIA II cards for the games. The G-Net is contemporary with Sega’s NAOMI and Taito tried hard to get developers to ditch NAOMI and move to the G-Net platform instead. Considering the vast number of games released for the NAOMI it’s fair to say that Taito didn’t succeed in their quest. There are only 22 known games released for the platform which makes the G-Net a quite niche system to collect. Nonetheless the G-Net boasts with a few major titles, like Psyvariar, Ray Crisis and Super Puzzle Bobble.

The Games

Taito G-Net System – Game Card

The games are distributed on PCMCIA II cards and any game settings and saves are stored back to the cards. The cards are inserted in the card connector on the CD PCB and a game card has to be inserted for the system to boot.

Most games can be found rather cheap both with and without artwork on for instance Yahoo JP. Most games can be picked up quite cheap (< $100) but there are a handful that fetch higher prices, like Psyvariar and Ray Crisis. Complete kits (including the box) on the other hand are hard to come by and will usually set you back way more.

Psyvariar kit (picture by Eiko at Arcade Otaku)

System Layout

Taito G-Net System
Taito G-Net System

The G-Net is comprised of three boards with two optional boards:

  • Sony ZN-2 Motherboard
  • Taito FC PCB (sound & flashROMs)
  • Taito CD PCB (PCMCIA II card interface)
  • Communication Interface PCB (optional)
  • Back Up PCB (optional)

Sony ZN-2 Motherboard (COH-3002T)

The Sony ZN-2 is based on the Sony PlayStation architecture and was licensed as an arcade platform to other developers, such as Capcom and Taito.

It conforms to the JAMMA+ standard and while most games use standard resolution (15 kHz) some games use 24.8 kHz (mid res) refresh rates. Thus requiring a dual sync monitor if it is to be used in an arcade cabinet. Taito uses their own BIOS for the G-Net version of the ZN-2, therefore called COH-3002T instead of the original COH-3000.

Taito G-Net System - Sony ZN-2 Motherboard (top and bottom)
Taito G-Net System – Sony ZN-2 Motherboard (top and bottom)

Taito G-Net System - Volume and Stereo/Mono switch

Close to the JAMMA edge on the ZN-2 board you will find the switch for choosing between mono and stereo along with a knob for the volume.

To the the right of the JAMMA edge there is six connectors; one each for a third and a fourth player, video, speaker, track ball and a connector for analog controllers such as the driving controllers for RCでGO!. I’m actually not sure if any of the G-Net games uses the track ball. Remember that the ZN-2 board is used for other systems as well as the G-Net.

RCでGO!Controller
RCでGO!Driving Controller

Taito FC PCB (K91X0721A)

The FC PCB connects to the ZN-2 and contains the sound hardware and the flashROMs for storing the game data from the PCMCIA card.

When powered up, the system checks for a PCMCIA II card. If the game data on the card matches the contents of the flashROMs the game boots immediately without delay. If not, the flashROMs are re-flashed with some of the game data from the card. This takes about 2 – 3 minutes after which the game resets and boots up. If no card is present on start up the Taito G-Net logo is displayed along with a “SYSTEM ERROR” message.

Taito G-Net System - FC PCB (top and bottom)
Taito G-Net System – FC PCB (top and bottom)

Taito CD PCB (J9100483A)

The CD PCB connects to the FC PCB and consists of a PCMCIA card connector.

Taito G-Net System - CD PCB (top and bottom)
Taito G-Net System – CD PCB (top and bottom)

Optional Communication Interface PCB (K91X0762A/J9100502A)

The communications board sits on top of the FC PCB and connects two or more units for simultaneous game play.

  • Up to four units can be connected simultaneously.
  • The units are connected in daisy chain from port 1 on one unit to port 2 on the next unit and so on.
  • On the first and the last unit in the chain the terminator need to be set to on. On the rest of the units switch it off.
  • Set the unit id using the knob in the center of the board. Number them in the order they appear in the chain.
  • The plugs are not Ethernet (RJ-45) plugs but RJ-11 plugs, commonly used for phones, with only two wires on positions 3 and 4. I don’t know if they’re supposed to be straight or crossed.
Taito G-Net System - COM PCB (top and bottom)
Taito G-Net System – COM PCB (top and bottom)

Optional Back Up PCB (J9100484A)

The Back Up PCB connects to the FC PCB. Unfortunately I don’t have any substantial information about the back up board.

Please drop me a comment or tweet if you have any info on the Back Up board. Thx in advance.

Taito G-Net System - Back Up PCB (top and bottom)
Taito G-Net System – Back Up PCB (top and bottom)

Modbios & Bootlegs

The security functions of the G-Net was cracked in 2009 and a modbios was made available. This allows users to use ROMs saved to standard PCMCIA flash cards instead of the original software. A few games have been hacked to work on the G-Net and thus are bootlegs. These are:

  • Aero Fighters Special
  • Brave Blade
  • Flame Gunner
  • Fighters Impact
  • G-Darius
  • Raystorm
  • Shanghai Matekibuyu
  • Sonic Wings Limited
  • The Block Kuzushi

Specifications

CPU – R3000A 32 bit RISC processor
Clock 50 MHz ?
Performance 30 MIPS
Instruction Cache 4 KB
Memory Bus Bandwidth 132 MB/sec.
OS ROM 512 Kilobytes
GPU – 360,000 polygons/sec, sprite/BG drawing, adjustable frame buffer, no line restriction, 4,000 8×8 pixel sprites with individual scaling and rotation, simultaneous backgrounds (Parallax scrolling), Sprite Effects rotation, scaling up/down, warping, transparency, fading, priority, vertical and horizontal line scroll
Resolution 256×224 and 740×480
Colours 16.7 million colors, Unlimited CLUTs (Color Look-Up Tables)
Sound CPU – Panasonic MN1020012A
Sound DSPs ZOOM ZSG-2, TI TMS57002
Other Features – custom geometry engine, custom polygon engine, MJPEG decoder
Media PCMIA II Cards
Optional I/O video, stereo, trackball, race controller, 3rd & 4th player, memory card
Onboard Memory present; saves high scores and settings including calibration but only per game
Communications Two LAN connectors plus terminator
Conversion Class JAMMA+
Speaker connector Pinout
1 L+
2 L-
3 R-
4 R+

The speaker output is amplified, hence no GND is used.

Video connector Pinout (unconfirmed)
1 Red
2 Green
3 Blue
4 Sync
5 GND
6 ?

The video connector connects an external 15 kHz monitor. I haven’t had the chance to verify the info on the video connector.

Sources

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