uses smaller connectors (although they're still the modular phone-style connectors).
Cat-3 cable is used for older 10Base-T networks. While existing Cat-3 cable is usually
serviceable, it is rare to see it in use today.
NOTE It is possible to run a Cat-3 network connection over Cat-5 cable. Because of this, many
companies installed the higher-grade cable, even if they didn't immediately need it, because the
cost of rewiring an entire building is very high.
Cat-5 cable has been improved and is now called Cat-5E cable. Also, an even newer
standard called Cat-6 has been approved. Both Cat-5E and Cat-6 are essentially the same
as Cat-5, but they meet higher-quality specifications to handle faster network speeds.
They are both also backward-compatible with the prior network types. In other words,
you can run a 100Base-T network over Cat-6 cable, even though only Cat-5 is required.
Using switches and hubs in concert
Cat-5 cable has been improved and is now called Cat-5E cable. In other words, you can run a 100Base-T network over Cat-6 cable, even though only Cat-5 is required.