Coaxial & Twinaxial Cabling

Coaxial

Coaxial (coax) cable is a different type of copper cabling, also carrying electrical signals.

Where twisted pair uses balancing to cancel out interference, coax uses two conductors that share the same axis
The core signal conductor is made of solid or stranded copper wire and enclosed by plastic insulation (dielectric)
then a second conductor is a wire mesh wrapped around the plastic
- serves both as shielding from EMI and as a ground
categorized using Radio Grade (RG) designations
- represent the thickness of the core conductor and cable’s characteristic impedance
- RG-6 is 18 AWG cable with 75 ohm impedance
  - typically used as a drop cable/patch cable for Cable Access TV (CATV) and broadband cable modems
- RG-59 cable is thinner and more flexible
  - used for audio/video and closed-circuit television (CCTV)
coax can be terminated using:
- Bayonet Niell-Concelman (BNC) connector
  - uses a twist-and-lock mechanism
- F-type connector
  - secured by screwing

Twinaxial (twinax) is similar to coax but contains two inner conductors.

used for datacenter interconnects working at 10 GbE (10GBASE-CR) and 40 GbE (40GBASE-CR4)
maximum distance is:
- 5 meters for passive cables
- 10 m for active cables
Twinax for 10/40 GbE is terminated using Direct Attach Copper (DAC) transceivers
- can be installed as modules in switch, router, and server appliances