How come most portable phone chargers use USBA rather than Micro USB for the output port? Is USBA supposed to be more tolerant? If they use Micro USB for the output (as well), the user could just use a Micro USB-to-Micro USB cable instead, which should be able to handle even 2A, right?


  • 1
    \$\begingroup\$ My guess is that MicroUSB-B -> USB-A cables are much more common. I've never even seen a dual-ended MicroUSB-B cable. \$\endgroup\$
    – Shamtam
    Commented Jul 14, 2015 at 15:11
  • 1
    \$\begingroup\$ Grab one of your double ended micro usb cables and have a look at it... oh wait, you dont have one, well... \$\endgroup\$
    – PlasmaHH
    Commented Jul 14, 2015 at 15:11
  • \$\begingroup\$ How come they're so rare? A chicken-egg problem? \$\endgroup\$
    – Kar
    Commented Jul 14, 2015 at 15:13
  • 4
    \$\begingroup\$ USB A & B cables are not supposed to have the same connector on both ends. \$\endgroup\$
    – pjc50
    Commented Jul 14, 2015 at 15:27
  • \$\begingroup\$ @pjc50 The USB spec does define a Micro-A to Micro-B cable, but I have never seen one "in the wild". \$\endgroup\$
    – user39382
    Commented Jul 18, 2015 at 5:35

1 Answer 1


The standard specifies USBA as the primary charging connector.

USBA makes much sense here as it is widely used on laptops and notebooks.

USBA is mechanically more rugged and reliable than Mini connectors.

There is a somewhat related discussion on this stack exchange question.


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