When converting a cabinet to use with MAME or other PC applications, you tend to find yourself hacking up a lot of cables, so that you can connect it to something like a GP-Wiz or I-PAC. Similarly to the J-PAC, the USBlinx is intended to remove that burden when using a JAMMA cabinet by allowing you to retain the original wiring and plugging the USBlinx directly into the JAMMA interface.

As described by UltraCade, the USBlinx is an interface for PC based systems to standard arcade controls. It supports 4 players with 4 buttons each, or 2 players with 6 buttons each. Additionally, it supports 2 trackballs and a spinner, making it an rather comprehensive solution to the PC interface problem.

All of the buttons and gadgets which you’d normally not be able to connect through JAMMA can be directly attached the USBlinx. While the USBlinx does have the option to use PS/2 for the keyboard inputs, the recommended connection is via USB, which gives you the un-ghosted keyboard inputs plus the trackball and spinner inputs as well. Since it is either a standard PS/2 device or a standard HID USB device, there’s no software required, and it will therefore support Mac, Windows, Linux, etc.

Other features include a built in audio amplifier for connecting your computer’s audio output to the built in speakers, a video pass through for connecting to the monitor, and a watchdog circuit to reset after a crash. Overall, it sounds pretty comprehensive.

The USBlinx package included all of the following:

- The USBlinx board.
- A printed manual, about 15 pages in length, and warranty registration card.
- One 6 foot USB cable.
- One 2-pin reset cable, for use with the watchdog feature of the card.
- One 3.5mm audio cable.
- One PS/2 cable.

Everything was well packed, especially the board itself, which was protected in an anti-static bag inside of a padded envelope.

Installation:

Installation is fairly painless. You connect the USBlinx to the JAMMA harness, and then connect whichever cables you need (audio, USB, power, etc). The USBlinx can take power from either a 4-pin molex connector from your PC’s power supply, or it can simply use the power on the JAMMA harness, if you have an arcade power supply installed in your cabinet. Their manual states clearly that you cannot connect both power sources at the same time.

A note now about the watchdog circuit, which caused me a lot of grief until I figured out what was going on. The USBlinx includes a watchdog circuit, which is designed to monitor the operation of the computer and ensure it is still operating. If not, it will send a reset signal to the computer (via the motherboard’s reset connector) and reset itself as well, just in case it’s the USBlinx which had crashed, and not the computer. The way that it determines whether the computer is operating properly is via the numlock LED signal.

It must be toggled at least once every 30 seconds, or it assumes failure and issues the reset. When testing, I didn’t have the reset cable connected, as there’s little need for it on the workbench. I also was not cycling the numlock state, and so the device would seem to “disconnect and reconnect” every 30 seconds. I went through several test machines before determining the cause of the problem. Downloading a small program that toggles the numlock LED automatically completely resolved this issue, but it is definitely worth mentioning, considering how much time I lost due to this.

There is nothing to configure on the USBlinx, so once everything is connected, you simply turn it on and use it. The key maps for the controls are not adjustable, unlike some of the other devices out there. The key map is shown below, and is included in their manual.

The USBLinx keymap - click for a larger image

As you may notice if you were planning to use this for MAME (and a lot of other emulators) there is no mapping for Esc, and the coin controls are mapped to 3 and 4, instead of 5 and 6. This means that you have to configure a custom key map for MAME. It would be nice to see an option for the USBlinx that offers default MAME key maps, or the option to install your own key map to the device. Not all emulators and front ends allow you to re-map the keys, so it would be best to check on the specific emulators you are interested in running before choosing this device.

Video:

The VGA input of the USBlinx passes video directly through to the JAMMA harness (and therefore your monitor) without any conversion or frequency adjustment, etc. If you are using it with an arcade monitor, your video card needs to output the appropriate frequencies. As reviewed in a separate article UltraCade makes a device called the uVC, which converts VGA to arcade frequencies, and does so quite nicely. It would be nice to see that as a feature on the USBlinx, or as an upgrade.

RetroBlast Review: Ultacade uVC

Audio:

The USBlinx includes a built in 2x37W audio amplifier, and the design appears to be a good one. I didn’t notice any distortion at all during my testing. Unfortunately, there is no adjustment for the volume of the amplifier, requiring you to adjust the sound solely from your computer. It would be nice to see a small pot on the board to adjust how much amplification is being done. The amplifier is definitely nice and loud however. I had to place my computer’s volume at around 5% to have a comfortable sound level in a quiet room. Obviously this would need to be higher in a setting with a lot of background noise, and so I would expect the unit could deliver more than enough sound no matter what your needs were.

Digital Outputs:

The USBlinx supports 4 digital outputs, designed for use with coin lockout solenoids and coin counters, as you’d find in most arcade cabinets. These work as expected, and are a nice feature.

Testing:

Once past the watchdog problems mentioned above, testing showed the device seems to be well designed, and we had no problems with any flakiness at all. The keyboard is responsive, the trackball inputs work flawlessly, and the audio is great.

Despite my best efforts, I couldn’t get the device to display any ghosting problems. So this is obviously (as mentioned in the manual) a non-issue. While the unit does include a PS/2 connector for use when you have no USB, it is for exactly that; only when you have no USB available. The USB connector carries both keyboard and mouse data, and is a more reliable way to connect the USBlinx to your computer. If you opt to not use the USB connector at all, you lose the trackball and spinner functionality, as it is only available on the USB connector.

After re-mapping some MAME keys, the unit was a lot more useful. As I said earlier, the default configuration has no way to leave MAME or to insert a credit.

While I did test the VGA pass through capabilities of the USBlinx, my testing was done primarily with an standard resolution arcade monitor. As such, I opted to use the UltraCade uVC instead of the VGA built into the USBlinx.

Overall Impressions:

The USBlinx does exactly what it’s advertised to do. Unfortunately, that’s probably not directly in line with what I believe most home arcade users would like. The non-MAME key map presents a minor irritation for most cabinet setups, but can be worked around by reconfiguring the programs you intend to use. The VGA output not having conversion seems odd, since most video cards don’t do well with arcade frequencies, and the company does offer their separate uVC card that handles this problem perfectly.

Pros:

- Excellent keyboard and mouse response times
- Single USB cable for all inputs
- Excellent audio amplifier quality
- No rewiring of your JAMMA cabinet is required for plug and play operation
- Coin counter support
- Watchdog circuit automatically reboots on computer crashes

Cons:

- Non-MAME key map, and key map not re-programmable
- Audio volume not adjustable on board
- VGA is pass through only, no sync massaging
- Watchdog circuit cannot be disabled

More USB Linx Information from UltraCade

Happ Controls: The UltraCade Universal Conversion Kit

List of UltraCade Distributors

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