Question 1

Will this work on piano?

Accepted Answer

It works changing a USB A port to a USB B port & vice versa. Do pianos have USB ports?

Question 2

What's the point of this kind of Adapter?

Accepted Answer

Devices that have control and provide power use the A connector. Devices that are controlled and consume power use the B connector.  
Think of As as outputs and Bs as inputs. Connecting two outputs together is risky (e.g. PC >PC), connecting two B inputs together is useless (e.g. printer to printer).

So why have the adapters?  In the early days of USB before the Standard was written that all Slaves would have B connectors (mini B, micro B, etc, just not A) many older slaves had A connectors and A>A cables were the norm. Most people had 1 computer and anything else was a Slave so A to A was probably fine.  Some of us have old Slave devices with A connectors and need a now obsolete A to A cable. These same folks might have a pile of obsolete A to A cables and use the adapter to get a B connector on one end.

I want to put a surge protector with a A and B connector near my device.  So my cable's B end will go in the surge protector, the A end of the adapter into the other end of the surge protector, and I now have the adapter's B connector to go into my device. The PC remains the output, my device remains the input.

To confuse things some of today's smallest devices have computers and Hubs in them and can be a Master or Slave or sometimes both. They may have a A or B or both A and B connectors where either can be both a input and output. Maybe the B is intended for the cable from the PC and the A is used for a cable to a portable drive but in place of the PC you have a flash drive with a A. Check the manual first, it may be ok to use this adapter to plug the flash drive into the devices B connector.  Personally I would not try it without knowing in advance it was safe and I would still be nervous. Seems to work for some.

So As are outputs, Bs and its variants are inputs, nearly all of the time....  Only use this adapter if you know why you need it.

I design and repair electronics. I've seen the damage of a A connector from a laptop to a A connector using an adapter on a car's entertainment system. Neither device survived...

Question 3

will this allow a usb wall charger to power a midi device that has the usb type B (printer) input?

Accepted Answer

I would like to say yes if your hooking it up to a charger, but I not 100% sure. I connect my phone and iPad to the printer to print stuff out. But it doesn’t charge my devices while it’s hooked up to the printer.

Question 4

Will this also force me to flip the usb around 2 times before I plug it in correctly?

Accepted Answer

Your humor is not lost on me... that is how USB A works... flip 2 times to make the connection every time it seems!

Electop2 Pack USB 2.0 A Female to USB B Print Male Adapter Converter

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