Is it possible to use atari 7800 trackball cx-22 and joypads for the msx computer? i see the pinconnector is exactly like the msx system.

and also atari st mouse?

MSX Joystick are atari-compatible. Only 1 trigger will be available, as 2nd one is an MSX variant.
Atari mouse protocol is different from MSX. Look at the bottom of this page:

http://retrospec.sgn.net/users/tomcat/miodrag/Atari_ST/Atari_ST.htm

thnx..

but i saw on ebay this one> also for coleco , c64, but also for msx?

coleco is also based msx systems right? with z80 controller

eBay link

{mod: changed the link}

Really strange
I think it will not work for MSX, as pin 5 is +5 V, pin 9 is GND and pin 8 is "strobe" for MSX mouse protocol. Maybe it will work as a joystick or do random responses...