follow the "Debug" section in the programmer's manual
http://www.qnx.com/developers/docs/6.4.1/neutrino/prog/devel.html#DEBUG
you'll find hints on how to use qconn via serial line
 

>-----Ursprüngliche Nachricht-----
>Von: Daniel Solomon [mailto:community-noreply@qnx.com] 
>Gesendet: Sonntag, 17. Januar 2010 22:08
>An: general-community
>Betreff: Debugging QNX software over serial connection from a 
>Windows machine
>
>I was wondering if it is possible to use Momentics to debug 
>software on a QNX (6.4.1) target over a serial connection.
>
>Usually I connect to QNX over ethernet (from a Windows 
>machine), by specifying the target's IP through Momentics. Is 
>it possible to do the same through a serial connection? If so, 
>could anyone point me to specific documentation regarding this topic?
>
>
>
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>http://community.qnx.com/sf/go/post45366
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