75 ohm cables are 75 ohm cables - marketing and the word 'digital' allows many companies to take advantage of you.
Here's the list:
Composite Video = One 75 ohm cable
S-Video = Two 75 ohm cables bundled in a single casing
Component Video = Three 75 ohm cables
Subwoofer = One 75 ohm cable
Coaxial Digital Audio = One 75 ohm cable
The cable from your cable company to your TV = One 75 ohm cable
VGA Cables = Five 75 ohm cables, plus extra cables, in a single jacket
Stereo Analog Audio = Two 75 ohm cables (most often, audio doesn't require 75 ohm cables!)
The ENDS of cables do not affect what type of cable is in between and adapters that go from one type of end to another are fine to use to get the cable connection you need.
That is, there is no such thing as a RCA cable. RCA is the connector on the END of a cable, and it does not determine the actual cable that is between the two RCA connectors.
Common connector types on the ends of 75 ohm cables:
RCA (most common, and typically color coded to indicate the typcal usage, even though this does NOT change the qualities of the cable) Yellow = Composite, Red/Blue/Green = component. Digital audio is often orange, while analog audio (stereo) is typicallly red & white.
S-Video - Round connector with 4 pins inside
DB15 or D-Sub 15 = The 15-pin connection on a VGA cable
BNC = Typically found on pro gear, it locks onto equipment and can't fall off.
F = The screw on end that you connect an incoming cable line to the back of your TV.
Quite often I will use RG-6 cable to send a subwoofer signal to a wall plate and I will put F-type connectors on both ends, then the wall plate will have a F-type connector on the back side, and a RCA type connector on the front. This way, the cable can lock onto the back side of the plate and never fall off, while I can use standard RCA ended cables to connect my sub.
