thanks for the response although I didn't understand your drawing modification
I would appreciate if you explain it within less tech level 
".... implement multi camera 360 deg...." [Are there more design details available.]
Edit #4 This Multi-Cam protect may be helpful:-
The $400, 96 Megapixel Panoramic [6] Camera
“Very Small Array” (VSA) by Max Lyons, March 2014
http://www.tawbaware.com/vsa_camera_array.htmlhttp://www.tawbaware.com/vsa_camera_array.pdf "...Gotchas
There are a few “gotchas” working with a camera array. Just dealing with 6 of everything (6 cameras, 6 batteries, 6 memory cards, 6 chargers, etc.) turns out to be a minor logistical challenge..."
And Multi-Cam protect "'Image Management":-
http://www.tawbaware.com/maxlyons/panostats.htm~~~~~~~~~~~
Some design Points to be considered [But one at a time]:-
1/ USB-2 Cable lengths and noise pickup problems.
There is NO Cable length limit in regard to +5v "USB 2 Remote Switch" for
Shoot_Sync i.e ALL cameras in "Parallel", I think of this as a camera "Write" or Shoot.
There is an USB-2 cable length limit of 5 meters, Pc to USB-2 Hub. i.e for camera Reads/Downloads
There is an USB-2 cable length limit of 5 meters, USB-2 Hub to Camera. i.e camera for Reads/Downloads
We are just combining two very dissimilar technology's by "Hacking the USB-2 Hubs" or Hacking the
Canon Camera Mini-B USB cable and adding some sort of control switching system.
ALSO the longer ALL USB-2 and Control wiring is the greater the probability that Mains. Audio, Radio, TV,
Computer, Wi-Fi, etc Noise will affect the Camera Shoot_Sync. This is why USB-2 Canon Camera Mini-B
cables have a Ferrite Noise Suppression Fitted. This also enables the cameras cables to pass FCC regulations.
However the control switching system will act as a Ariel and pick up stray noise which will randomly affect
the Camera Shoot_Sync. see attached file. Attack+Decay-USB 1.png i.e. "USB Jitter"
There will also be some "USB Jitter" just due to difference's between USB Hot_Plug switch point's in canon cameras this will affect the multi-cam array Shoot_Sync.
Also See this post;- Re: Sync Multiple Cameras Reply #4 on: 02 / March / 2012,
http://chdk.setepontos.com/index.php?topic=7758.msg82144#msg82144Edit #1 The "USB 2 Remote Switch" is not a Differential cable system and is more likely to be affected
by common mode noise pickup. i.e. for Shoot_Sync
Edit #2 The USB-2 cable uses twisted pairs to reduce induced noise. i.e. it is a Differential cable system.
See attached file; USB Cabling & Device Classes
H-H
to be continued....
Edit #3 May be this post has some effect when trying to sync multiple cameras:-
CHDK task repeat interval timing precision (USB Remote Pulse Accuracy) 02/June/2014
http://chdk.setepontos.com/index.php?topic=11558.msg113210#msg113210
