Timeline for USB vs Ethernet cable length
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 26, 2016 at 4:43 | comment | added | Ale..chenski | Wikipedia is wrong about the reason of USB2 cable limitations, it is the other way around. The limiting factor is in cheap cable and cheap single-amplitude drivers with no pre-emphasis nor frequency equalization at receiver end. As result, it is economically difficult to deliver an open signal eye on the far end of 5m USB cable. The 1.5us (actually 1.7us) response limit then comes from star topology of 5 hubs (each having inherent prop delay in repeaters) , and 400ns device response time. | |
| Feb 7, 2013 at 11:06 | comment | added | pjc50 | superuser.com/questions/203757/… USB 3 has a shorter maximum cable length. | |
| Feb 7, 2013 at 10:05 | comment | added | zzz | Ethernet is completely different beast, but I wonder how USB 3.0 (As it is much closer to USB 2.0 than Ethernet obviously ) circumvent this limit? | |
| Feb 7, 2013 at 9:22 | comment | added | John U | Original Ethernet was designed in a different era when there were different priorities & costs to components & complexity VS cable. USB is designed very much with the lowest possible cost & smallest footprint / connector / cable / power use in mind for Joe Bloggs and his iPhone. | |
| Feb 7, 2013 at 3:44 | comment | added | PeterJ | @LukeQuinane, no I don't know much about the Ethernet physical layer. I suspect though the overall decision for USB was made to keep the device costs as low as possible by keeping the drivers simple. | |
| Feb 7, 2013 at 3:29 | comment | added | Luke Quinane | @PeterJ that's very interesting. Any ideas how ethernet avoid that problem? | |
| Feb 7, 2013 at 3:26 | comment | added | PeterJ | @LukeQuinane, I just noticed the reason is mentioned just above the area in the link you posted, usb.org/developers/usbfaq#cab1 | |
| Feb 7, 2013 at 2:38 | comment | added | Luke Quinane | I guess the question is why did they limit the maximum round trip time to 1.5μs? Initially I thought it was because of the high transfer rate but ethernet avoids that problem somehow. | |
| Feb 7, 2013 at 1:08 | history | answered | Littleman | CC BY-SA 3.0 |