USB Cable – Why Do Some USB Extension Cables Have an Extended Shroud?


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.

USB Cable comparison

Best Answer

USB 2.0 extension cables are illegal from USB specification standpoint. This is because the extra imperfection along USB 2.0 transmission line causes massive degradation of signal integrity.

So no test procedures nor acceptance criteria are there, and anyone can craft whatever they feel. There are more variants of overmolds, like this one below. Use at your own risk. Works fine for me though.

An example of a USB cable without a protective sheath around the connector.

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