There's one point I would criticize in that LanShack link:
[Linked Image from lanshack.com]
Quote
In telephony the terms that represent the conductors that compromise a circuit are known as “tip and ring”. These terms stem from the early days of telephony when operators made telephone connections using ¼” phono plugs similar to those used today for stereo headphones. The old systems also carried a third wire which was a ground. The “Tip” was the tip of the plug and was the positive (+) side of the circuit. The “Ring” was a conductive ring right behind the tip of the plug and was the negative (-) side of the circuit. Right behind the ring was the “Sleeve” which was the ground connection.
The sleeve connection was not just a ground. It was used for supervisory functions on circuits within the central office -- Holding a switching train until the plug was removed, for example.

Oh, and I think they meant to say "comprise the circuit" rather than "compromise the circuit." [Linked Image]