Read through the discussion, still does not have a solution. Here a more detailed problem description: We need to remotely capture image using digital cameras, and then download the images to computer. So far we have tried the following: 1: Camera set to external USB mode, using a relay to cut off the 5V line, works, but not reliable, once in a while, kills a camera. Advantage of this method is download speed is good. 2: Camera set to remote camera using WIA (Nikon DSLR has these), we don't need to cut off the USB, the problem is the downloading speed is very slow, and if user happens to view image in the camera folder, the camera capture is very hard to get synchronized, since the camera is acting as a "server", busy working on too many things. We are currently using the tethered method, communicate with camera using windows WIA method, solved killing camera issue, but created synchrization and download speed issue. We want to try the USB downloading method again, since we have too many images and speed is important now again. -- Youda On Tue, Jun 2, 2009 at 8:48 PM, Xiaofan Chen wrote: > On Wed, Jun 3, 2009 at 11:02 AM, Mark Rages wrote: > > On Tue, Jun 2, 2009 at 9:47 PM, Jinx wrote: > >>> Consider the USB 2.0 is high speed device, what type of switch > >>> could we use ? > >> > >> Analog Devices, Maxim and Vishay make high-speed TTL switches, > >> some with very low Ron and capacitance. Even the 74xx4066 might > >> do, or analog selectors like the 74xx4051 > > > > When I was looking at analog switches last week I saw some that were > > rated for USB. I don't remember where; try Maxim, Analog or TI. > > > > Why are you disconnecting USB? is it just to unmount the memory card? > > Maybe try just switching off the 5V line off with a transistor. > > > > Similar discussions here. > > https://www.usb.org/phpbb/viewtopic.php?t=12856&postdays=0&postorder=asc&start=0 > > > > -- > Xiaofan http://mcuee.blogspot.com > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist