You can source a longer 15-conductor cable if needed for your imager. Ensure that all 15 pins are physically wired inside the cable. An easily identifiable symptom of a wrong cable is that the scan head will light up with a blue light. We recommend the following cable for a longer 15-conductor cable:
http://www.cablestogo.com/product/50213/10ft-select-vga-video-cable-m-m-in-wall-cmg-rated
Under the product features of the cable linked, they list that all 15 pins are wired to support DDC2 (E-DDC) and EDID.