Re: USB (or Serial) vs Ethernet: Which is better or more reliable?
Hi, Petertoggle quoted messageShow quoted text
I'm not quite sure what you mean by "trust" here. The protocol spoken to and by your mount is comprised of very short ASCII character sequences - nothing like bulk binary data like which you'd see from your two cameras (main and guider). If you're already running USB to your pier for your other accessories, the mount isn't going to amount to much else in terms of perceived instability. It, like a focuser or filter wheel, has a very simple protocol with exceedingly low bandwidth requirements. USB will handle it fine.
It will note, however, that 35 feet for a USB run is *double* the maximum length specified by the USB 2.0 spec, as the maximum length in order to maintain USB 2.0 Hi-speed (480Mbits/s) is 5 meters, or a smidge over 16 feet. In this case, I wouldn't be surprised if the run between your computer and the hub you have on your pier has fallen back to USB 1.1 Full-Speed speeds of 12Mbits/s. Obviously, since you're imaging, that would be or is sub-optimal. You low-bandwith devices such as mount and focuser will still be fine, but downloading images off your cameras will be slower than it should.
You have 2 options in that case:
1. Get an Active USB 2.0 extension cable, also known as repeater cables. The throw distance on these are far greater than the 5 meter limit of USB 2.0. Examples can be seen here: http://www.yourcablestore.com/Active-Repeater-Cables_c_166.html
2. Move your PC physically closer to your pier in order to cut down cable length. I reckon that you would have done this already if you were able to, but it bears mentioning that small x86/x64 computer systems in industrial chassis are pretty ubiquitous now and are small enough that that can live *on* the pier itself. Running windows and file share services on it, you can remote desktop into it and use SMB file shares to offload photo data over an existing 802.11 or hardwire ethernet network.
On Sep 15, 2018, at 2:47 PM, firstname.lastname@example.org [ap-gto] <email@example.com> wrote: