Hi,
I was connecting another 4 port USB hub to a machine tonight "identical" to one already in service, there. Once in place (and operated in the same fashion as its sibling predecessor), it failed to operate as expected! (i.e., PC wouldn't enumerate any of the drives attached).
Suspecting the hub might be bad, I tested it elsewhere. Replaced cables. Added external power source. etc. Works like a champ on another machine (with different devices dangling off of it).
[remember, "old" hub still works fine on the machine of interest]Tried a *second* hub (which is actually the *third* of this type being discussed) with similar absence of joy.
After enumerating the behaviors of the three different hubs (one "good", two "bad" -- yet all *functional*), I took a peek inside. Of course, different chipset in the good vs. bad ones.
Aside from an intellectual curiosity, this is not a real issue for me *personally*. I'll just pick up another couple of hubs.
But, I had been debating what to use for external interconnects on a high volume project. USB (host) *seemed* the natural choice. It's always "just worked" (for me) in the past!
In light of this little experience, I started thinking about how I would respond to a customer making the claim that *my* device "wasn't working" -- when he attached (this particular) hub/device. Yet, *swearing* to me that these things worked properly "elsewhere".
I've been giving serious thought to using ZigBee/BT for external device connections as it offers several other advantages over USB (no wire tangles, longer "virtual" wires, no cables to keep track of, no connectors poking through the case, no galvanic paths back *into* the device, no concerns about supplying "enough" power to the external devices, etc.). Of course, the ubiquity of USB and the huge cost advantage have (previously) been weighing against the wireless approach. :<
So, for folks with USB-capable (host/slave) devices, what have your experiences been:
- problems as a host NOT recognizing some bit of COTS kit dangling off your port (that the user thinks you *should* be able to recognize -- e.g., "generic hub")
- problems as a slave NOT being recognized *through* some particular combination of fabric to the host And, how do you address these problems when interacting with the customer? How happy is he/she with your remedy ("buy a different hub", "buy a different disk drive/printer/smokeshifter", "plug in the cable BEFORE applying power", "plug in the cable AFTER applying power", etc.)
(I.e., the wireless solution may win because it is LESS ubiquitous... less likely to be "expected" to talk to "anything with the correct connector onboard")
Thx!