# Why does USB-B exist? (computer cable)

**URL:** <https://boards.straightdope.com/t/why-does-usb-b-exist-computer-cable/1031930>\
**Category:** Factual Questions\
**Created:** [July 26, 2026, 1:01pm UTC](https://boards.straightdope.com/t/why-does-usb-b-exist-computer-cable/1031930 "2026-07-26T13:01:02Z")\
**Posts on this page:** 1\
**Showing post:** 152

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [July 29, 2026, 1:00am UTC](https://boards.straightdope.com/t/why-does-usb-b-exist-computer-cable/1031930/152 "2026-07-29T01:00:17Z")

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Right, your portable battery pack can do that, because it’s new, and they eventually figured out how to make devices smart enough to do that. Eventually. They didn’t have that when USB was first invented. A portable battery pack from the early days of USB would have to have had two different sockets, one to charge the battery, and one to use the battery to charge other devices.

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