Maplin follow up

[CoastGuardJon]

When I got to play with my RB (2009 label)  supplied by Maplin Electronics, I found the USB A to USB mini B lead supplied was U/S.    I emailed Maplin and they sent a replacement lead, which I found to be USB A to USB B type (L00BT) despite it being quite clear in my email that it is the A - mini B type required.    I rang customer services at Maplins, no hassle whatsoever, "we'll send the correct type FoC and don't want the U/S or incorrect lead back.  Which lead do you require?" I pushed my luck a bit and asked for the L10BT which is the 5metre lead.   Received the lead today and have had a quick test, it powers up the RB fine, with blue LED flashing but no white LED or a/c displayed, opened up the window and stuck standard twig on the roof - white LED started flashing and 3 a/c appeared, including 2 over Ireland, some 180 miles away, so it would appear that the 5m lead is fine with the RB.    If the weather's quiet over the weekend, I'll try some day-time snooping and see what I get.

Anyway to the point of this post Maplin's follow up excellent!

[Fenris]

Jon, just be aware that a 5m lead of that type may work with the particular USB host and device you're using today, but may not do so in all cases depending on the different host in use and the current its USB port(s) will supply.

These things can be very finicky.

As a technology, ethernet is nicer because it uses the multiple pairs in the cable as parallel data paths, so each one goes more slowly and has more margin against dodgy cabling, poorer driver strength in the transceivers and so on. USB puts all its eggs on the one data signal pair in the cable, so that runs at full interface rate and so it pushes the envelope a bit more.

USB is very sensitive to the physical routing between the transceiver chip and the USB socket too, even with a top notch cable this can still be a bit iffy.

Luckily the RB interface runs fairly slowly, 12Mbps I think, which is quite slow. But still it can be picky about cables etc.