2
Some of the USB 2 extension cables in my collection have an extra sheath or shroud at the female end, with the type-A socket recessed inside by a few millimeters.
Is there a reason for this? Is it standardized or documented anywhere?
In the attached photo, from left to right, the type-A socket is,
- Flush with the sheath, works with all plugs and devices.
- Recessed about 3mm, works with most plugs and devices.
- Recessed about 5mm, works with very few plugs and devices.
The cable lengths are approximately 32in, 16in, and 20in, respectively. They are passive extension cables.
jamieguinan
Posted 2018-02-22T21:55:39.007
Reputation: 123
Note, I googled various permutations of "usb extension" with "sheath", "shroud", and "recessed", but I could not find an answer. – jamieguinan – 2018-02-22T21:57:20.230
One of those look like an active cable. What are the lengths of these cables? USB 2 or USB 3? – Ramhound – 2018-02-22T22:09:37.047
From left to right. 32in, 16in, 20in. USB 2. They aren't active, as far as I can tell. No enumeration when I plug any of them in. – jamieguinan – 2018-02-22T22:20:52.407
Update your question. – Ramhound – 2018-02-23T00:03:14.757
I suspect it has something to do with the fact these are extension usb cables, which I have only ever seen being active, as for the differences I suspect that’s linked to their length. – Ramhound – 2018-02-23T00:08:41.947
The white cable seems to be a special case. Beside the recessed connector, it also has a ferrite choke on it. I have a dozen (passive) USB extension cables of various lengths (6" to 10'), and all have a minimal recess or shroud, and no ferrite donuts. – sawdust – 2018-02-23T01:29:07.827
USB2 extension cables are illegal from USB specification standpoint. So no test procedures nor acceptance criteria are there, and anyone can craft whatever they feel. Use at your own risk. – Ale..chenski – 2018-02-23T02:06:57.110
Despite the USB specification, variations of USB extension cables are in widespread use, e.g. the connections between a motherboard and the front-panel ports of a desktop case. – sawdust – 2018-03-01T20:59:24.613