Welcome to Networking — Episode 02
Twisted Pair, Pin Outs, and Cable Categories
August 14, 2026 · 12:46
Prefer YouTube? Watch this episode on the channel — comments and questions live there.
About this episode
Cabling is the subject everyone is assumed to already know, so nobody stops to explain it. This episode explains it. By the end you will sound like you have years of experience.
We start with one twisted pair and why the twist is there at all, which is a better story than it sounds. Then we terminate four pairs under T568A and T568B, and look at what a wire map catches when someone got it wrong.
Then the part that costs people money. A cable category is a set of electrical performance limits over a frequency range. Cat5e to one hundred megahertz, Cat6 to two hundred fifty, Cat6A to five hundred. Those are frequencies, not Ethernet data rates. Knowing the difference is what stops you from buying the wrong cable for the next ten years.
Chapters
The same chapters as on YouTube, so you can find your place in either player.
- 0:00 Three layer one topics
- 0:34 Differential signaling
- 0:58 Why the pairs are twisted
- 2:32 Inside the cable
- 3:14 T568A and T568B
- 4:43 Wire maps and faults
- 5:14 Walking into a site that already exists
- 6:15 What a category actually specifies
- 7:26 Gigabit uses all four pairs
- 9:34 Ten gigabit on Cat6, and choosing Cat6A
- 10:24 Multigigabit Ethernet and access points
- 11:41 How layer one faults behave
- 12:14 Outro