again like everyone else RCA is only 2 channel stereo wile the optical gives you the full 5.1 (so does the digital coaxial, you can use one of the red or white rca cables to go from the appropriately labeled "digital coax" or "spdif" its usually orange or black)

so ultimately you could get a cheaper video card with just a digital coax, its one step below the optical. but if you have the money... just get the optical card and cable.

and sidenote- HDMI and optical are not the same, they now have this "HD audio" on alot of blu-rays that will only be carried by hdmi and recognised by "HD audio" ready players and recievers. i wish i could own it all instead of just install it haha

An optical Fiber is one of the most efficient modes of data transmission; it is a thread like structure and transmits data in the form of light waves. For efficient working of an optical Fiber it must be timely checked and tested. A Fiber optic tester is a device used to detect any defect that could harm the transmission efficiency of an optical Fiber. An optical Fiber can face two defects contamination. Damage of the first one refers to the deposition of dust gum or oils in the transmission path and the latter refers to the cracks or pits formed in the Fiber.

These defects can be detected using a Fiber optic tester. There are three different types of Fiber optic testers available, first are the continuity testers, which use a light source that transmits light from one of the Fiber and detect the light at the other end. These testers just tell whether the Fiber is defected or not, they do not provide information about the defect. Next is the insertion loss testing which provides information about the total loss in the Fiber per km and also highlights the bends, splices and links in the Fiber. Last is the OTDR it stands for optical time domain reflectometer, it provides complete information about the Fiber; its length splice losses, connector losses and Fiber defects and stores the information electronically. It is one of the most advanced Fiber optic testers.

After completing the Fiber optic testing the defects must be removed and this is done by cleaning Fiber optic cables by using special solvents like isopropyl alcohol or by air blasting for cleaning Fiber optics. All these Fiber optic tools are a part of Fiber optic testing equipment.