Mac Forum / General / Hardware / February 2010

I don't know the answer to your question.

I do know that I've taken such cables and forced ordinary male
connectors into that notched female connectors, and except for the
fact that this was very hard to do,  it has worked fine.

(I think the only devices I've done this with are keyboards though.)

I think it was to ensure that you were using a high quality cable as the
keyboard has a hub built in for the mouse etc, however it does seem a
touch pointless as you could replace it with any USB extension cable
(however USB extension cables were quite scarce in the early days).
Ben.

apple used to provide keyboard extension cables that could only be used
for extending the keyboard. it was incredibly stupid.

Nearly no other USB extension cables have this 'lock', which can mean
that the plugs can easily be taken from each others and you siddenly sit
with a 'non-working' keyboard. - I have had this 'problem' with one of
my friends. - Suddenly he calls me to tell that he can't do anything
with his mouse or keyboard... He has one of the extension cables without
the 'lock', so I told him to just looke if the plugs were connected
beneith his writing table... I think you can guess the rest..-)

This extension cable was/is dedicated to and delievered along with the
black/silver and white Apple Pro keyboards, which all have the short
'tale', where some of the dedicated iMac keyboards could be either with
a short or long 'tale' - as well as the 'hockey-puck' mouse...

Cheers, Erik Richard

For some reason, Apple thought it was a good idea to supply some of
their keyboards with relatively short bonded USB cables, but included an
extension cable with models where it was likely that the computer would
be installed some distance from the desktop (PowerMacs and similar).

The USB standard does not allow the use of extension cables with
arbitrary devices. The female "A" connector is never supposed to be used
on a cable. Any such cable you happen to be able to buy cannot be
certified as compliant with USB.

Apple's keyboard extender cable has a notch to prevent it being used
with other USB devices. Its use in conjunction with the keyboard is a
known pairing which Apple can test and establish that the combination
complies with USB electrical and signalling standards.

The notch also ensures that only one extension can be used with the
keyboard.  You can't daisy-chain them.  This means Apple doesn't have
to make the keyboard work with an arbitrary length of USB.

Aloha:  would you like to sell some of them to me?  I need 5.

wendell au   techvalet@hawaii.rr.com

The USB spec doesn't (or didn't) allow extension cables.  The cable
actually works fine with other stuff if you force it or remove the
bump.