[NTLUG:Discuss] OT USB standards

[agoats at compuserve.com]

You're all suffering from mechanical tolerances to the connectors. If 
you go and get the USB 2.0 standards at

http://sdphca.ucsd.edu/Lab_Equip_Manuals/usb_20.pdf‎

Chapter 6 has the mechanical dimensions, and what is happening is a 
variety of :
1 maximum tolerance male to minimum tolerance female = tight fit
2 minimum tolerance male to maximum tolerance female = loose fit
3 minimum tolerance male length and maximum tolerance length (depth) 
female = not so good electrical contact

and so on. Worst case design says it should always work, but as you get 
some wear, the performance goes down.

I'm suffering some of the same issues with SATA connectors: they lose 
contact with the drive.

Alvin






On 02/14/2014 08:53 PM, Christopher Cox wrote:
> On 02/13/2014 05:50 PM, Fred James wrote:
>> OT: USB standards
>> In particular, the physical dimensions of the connections
>> Why are the connections not all the same size ... even within one brand?
>> In trying to plug a USB stick into a computer USB port I find some loose, some
>> tight, and some just too big to fit at all.
>> What's up with that?  Is this like other "industry standards" ... not standard
>> at all?
> The ones that are the worst are the plastic sheathed ones.  I guess they have to
> make it a bit thicker.  Oh... I'm talking about USB sticks of course.
>
> I have an USB SDHC adapter that fits really tight in my Cubox... oh.. and again,
> I'm talking about a USB adapter and a USB port.... in case there was any
> question about that.
>
>
>
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