Hello guys,I have a hobbyking 6ch transmitter,which doesn't come with any display,and there is something wrong with my pitch channel.I connected it to my kk2.1.5 flight controller for a reciver test and when I move my stick  forward,the flight controller shows that it goes all the way back! .And when I move my stick back,the controller shows,it goes forward.How do I change this?,it doesn't have any screen.

Usually there should be an interface to connect it to a computer ..

I think I dont have the usb,maybe I've lost it.Is there any other way?

If the tx is ct 6b then there is a way to connect if you any usb to serial converter either arduino or cp2102 module.
You will have a software available for pc from which you can reverse a channel.