Originally Posted by mixture
Would you care to enlighten us as to which particular law of physics you are invoking to transform a physical (non-optical) cable into a one way medium ?
It is not the cable itself that is one-way, it is the interface at the computer end, which is designed to supply power, not receive it. You can't poke power back through a regulator. Check out some reg chip designs.
http://www.datasheetcatalog.org/data...s/tl780-05.pdf
The specification for usb says very clearly that the power flow in the cable is one-way, taking power from a computer to a peripheral.
USB.org - Documents
Originally Posted by hellsbrink
You might be able to buy a "universal" laptop charger
Avoid these like the plague. I found they really mess up the electronic innards of the laptop battery. Always use the correct charger from the oem.
If you can't carry the charger one solution is to carry a spare fully charged battery of the correct type for that computer. Expensive items but easily affordable on pilot pay, and prossibly tax-deductable.
Edit: Take care to carry in an appropriate container with protection against shorting of contacts. Li-ion batteries present a major fire hazard if mis-handled.
When caught short use a public access terminal at a library or internet cafe. And enjoy the excellent coffee.
If there is private information you need in transit the best way is to email it to yourself, then you can pick it up from any terminal anywhere.