FM Towns:Video Information
Video display
FM Towns video connector was a DB15, two-row connector that was very common for other Japanese computers such as the Sharp X68000 and PC98. The uniqueness of FM Towns is that the computer was capable of displaying 15khz, 24khz and 31khz signals.
Modernly there are almost zero monitors that can display all video settings and modes.
24khz display mode appears to be used exclusively on the startup/power on screen and in DOS modes. Generally, it is more important to have support for 15khz and 31khz as it is quite rare for games to run in 24khz. The photo on the right is an example of a display not working with 24khz.
Connector Pinout
Check the photos for the pinout information. Overall it's very similar pinout to X68000 and PC98.
- FMT RGB PINOUT.png
FMT RGB Pinout.
Pay attention to the red arrow. That is the RGB connector
How to connect it to anything
If you're not using a Japanese CRT to play games you might consider a video processor or converter. However the DB15 connector won't work with the VGA connector on something such as the OSSC...yet. You will likely need a connector or converter for the pinout. Sanwa supply makes the one in the photo and they're readily available on the net. Some users have reported using the Mac DB15 to VGA connector as well.
DB15 to VGA Connector.
Recommended Video Processors that have been used and tested
These are used by several people using Retro PC and Japanese Retro PC specifically.
- OSSC via VGA.
-Handles most resolutions and frequency very well although some displays still hate the resolution output by OSSC specifically in 24khz.
-That isn't an indicator of a problem with the OSSC itself. - XPC4 via VGA.
-It can output S-Video, Composite, VGA or DVI video.
-One output at a time.
-It can also change the output resolution up to 1080P.
-Multiple users either use this with an LCD or even an IBM CRT as the XPC4 outputs a 31khz signal from the VGA outport.
-Also significantly more expensive than OSSC at close to $350 USD shipped from Japan - Retrotink5X with a device such as the HD15-2-SCART, VGA2SCART converter or any other device that converts RGBHV to RGBS.
-The Retrotink5X handles video and resolution switching just as fast as the OSSC.
-The Retrotink5X cannot display 24khz video modes at all. It will show a blue screen.
Some FM Towns Computers that output 31khz
The 3 slot desktops (EA/ME) and Pentium will output 31khz RGB. They perform internal video conversion and sometimes you don't need to make a cable or video processor at all! The EA-type desktop and Pentium desktops will have a normal VGA connector on them. Even the 24khz video display modes will output 31khz and this includes the startup screen.