Let's consider a theoretical keyboard which has BT and USB interfaces (haven't see one yet - pointers would be appreciated).
Let's say it's paired with a notebook, and then connected by USB cable to the desktop to charge.
How it should behave?
"sending keystrokes to both sides" is out of consideration, I hope. Too clowny.
Should USB have preference? Or BT? Configurable setting? Last device connected? Any other ideas?
Q: how BT+USB keyboard should behave if both interfaces are connected?
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DMA
- Location: Seattle, US
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Findecanor
- Location: Stockholm, Sweden
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I think USB should have preference. The reasons:
1. The keyboard might have been paired over BT to something else. The explicit action of plugging it into a device shows user intent to the keyboard that it should start talking with the one that is plugged in. An exception would be if the "host" does not actually act as a host but only delivers power (having only a power-delivery protocol does not count as being a host).Another might be if the user through an explicit action (key combo or switch etc) has locked the pairing, but that is less likely, could cause confusion and should therefore not be the default.
A keyboard should act like a conventional keyboard as much as possible. It's the classic rule "an interface should never surprise the user". A new user might not even know that it is a Bluetooth keyboard or how a BT keyboard works.
2. USB is safer than BT. BT has weak encryption that can be cracked (or may be cracked in the future) where as USB is a physical interface.
3. Use as much power as possible to charge the battery. I think USB signalling uses less power than BT, but I might be wrong. It feels intuitive that it does.
4. Do automatic pairing over USB (if you have the right software installed on the host). Apple's "Apple Magic Keyboard" does this on MacOS X.
1. The keyboard might have been paired over BT to something else. The explicit action of plugging it into a device shows user intent to the keyboard that it should start talking with the one that is plugged in. An exception would be if the "host" does not actually act as a host but only delivers power (having only a power-delivery protocol does not count as being a host).Another might be if the user through an explicit action (key combo or switch etc) has locked the pairing, but that is less likely, could cause confusion and should therefore not be the default.
A keyboard should act like a conventional keyboard as much as possible. It's the classic rule "an interface should never surprise the user". A new user might not even know that it is a Bluetooth keyboard or how a BT keyboard works.
2. USB is safer than BT. BT has weak encryption that can be cracked (or may be cracked in the future) where as USB is a physical interface.
3. Use as much power as possible to charge the battery. I think USB signalling uses less power than BT, but I might be wrong. It feels intuitive that it does.
4. Do automatic pairing over USB (if you have the right software installed on the host). Apple's "Apple Magic Keyboard" does this on MacOS X.
Last edited by Findecanor on 15 Apr 2018, 04:35, edited 2 times in total.
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DMA
- Location: Seattle, US
- Main keyboard: T420
- Main mouse: Trackpoint
- Favorite switch: beamspring
- DT Pro Member: NaN
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Oh, you mean shutdown BLE on USB connection. Have not considered that.
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DMA
- Location: Seattle, US
- Main keyboard: T420
- Main mouse: Trackpoint
- Favorite switch: beamspring
- DT Pro Member: NaN
- Contact:
implemented USB priority in the end. Too lazy for doing another configurable option 