KVM requires me to power on both computers.

I am using a KVM switch (TRENDnet TK-207) to share my apple keyboard and mouse between my Mac Pro (early 2009) and my mac mini (intel) .
Everything works pretty much normal as far as mouse functions and keyboard functions, I can switch between the two normally.

The problem comes when both computers are powered off and I go to power on the Mac Pro, the KVM just blinks until I turn on the mac mini, then it will let me use the mouse and keyboard on the mac pro.
I can shut down the mac mini and the KVM will continue to work normally until I power off the mac pro.
I can put the mac pro to sleep and it will awake and the KVM will work normally.

What should I be doing to find the problem?

 

The mac pro.
When I get a chance I am going to try to see if I can power the mac mini with the mac pro off and see what results I get.

I have switched the ports on the KVM but same issue.

 

Same thing occurs when I start the mac mini without the mac pro on, I have to turn on the mac pro before the mouse and keyboard will work.