USB cable camera triggering for RC systems
To operate with Canon cameras the camera must have a minor enhancement called SDM or CHDK added to the camera via the SD card, which enables operation of this device as well as many other creative possibilities for remote photographers. There are more details on this here.
gentWIRE-USB is the basic model allowing control of one camera function - normally the shutter - from one RC receiver channel. This can normally be done without running a script in the camera.
gentWIRE-USB2 is an advanced solution using 2 RC receiver channels, and allowing 6 different commands to be sent to the camera which can be programmed via the CHDK Scripts to control many functions (e,g, Shutter, zoom, EV, focus etc).
More Information: Operating Manual (USB), Operating Manual (USB2), Guide to SDM.
wired USB camera shutter control via RC: