external SSD drives and importance of good cables

Started 2 months ago | Discussions thread
Sean Nelson
Sean Nelson Forum Pro • Posts: 16,054
Re: What is a "good" cable?

Chris Noble wrote:

That's not the situation here; the data lines are there, they are just slower than they are in other cables. So why is one cable "faster" than the other if they have the same number of conductors?

USB is a collection of protocols that have been introduced over multiple decades.  The original USB 1.0 spec was 1.5 mbit/sec, but subsequent versions have increased the speed over time.

One of the reasons USB is popular is that each new, higher-speed version has been backward compatible with previous versions, both in terms of the physical connector (up until USB C) and also in terms of the electronic protocol.   So you could have a USB 3.0 port on your computer and plug a USB 1.0 mouse into it and it will work fine.   Or you could take your USB 3.0 external hard drive and plug it into a USB 2.0 port and it will also work.

When you plug one USB device into a port that uses a different protocol, the two sides negotiate to figure out what the capabilities are, and agree to use the "least common denominator" protocol.  I'm guessing that this negotiation chooses whatever transfer rate the cables are capable of achieving.

USB cables are not simple wires like you'd find in a lamp cord, but very carefully designed and manufactured products with specified wire sizes, wrapping and twisting.  Marginal cables may not be able to perform at full rated speeds.

Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark MMy threads
Color scheme? Blue / Yellow