20 Aug
2012
20 Aug
'12
10:22 a.m.
On 20 Aug 2012 at 9:51, Eric Smith wrote:
The USB specification prohibits use of standard
detachable cables with
low-speed devices, because they exceed the maximum allowable cable
length and capacitive load for low-speed (Sections 6.4.1 through 6.4.4
of the USB 1.1 and 2.0 specs). Normally low-speed devices use captive
cables. Vendor-unique detachable cables may be used; this means that
they can't use the normal USB B connector.
Of course, and I believe that the V-USB site makes this very clear.
I've got a carton of early USB HID peripherals with non-detachable
cables. They all use the Intel N82930A3 controller (68 pin PLCC) No
modern (i.e. 2000-present) system even sees the things--that's an
indication of how far USB has come.
--Chuck