An interesting issue, I wouldn't have guessed before.? ?USB cables that don't pass USB testing are being sold (without notice) that they are "Charge Only" cables.? Unlike in the past apparently.?
You must only purchase a cable marked "Charge & Sync" to actually get a real USB cable.? ?
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Some are just intermittent. The first one I found connecting my iPhone for Apple Play (new cable identical to the one I have used for several years) is intermittent.? Then no connectivity for 2 each USB A to USB C cables with no marking "Charge Only" conveniently at the checkout counter on my last business trip.? Fortunately I only needed them for charging.? These were priced at $19.99.? Meanwhile a "Charge & Sync" cable on another isle (Staples Brand) in 10 Foot length only $9.99.? Bought 2 and they both work great on QMX and QMX+ and Apple Play.??
Dave WI6R