Question: What's the difference between Cat 5, Cat 5e and Cat 6? Can I use one in place of another?
Answer: The difference is in the bandwith ratings. Cat 5e has a higher bandwidth than Cat 5. Cat 6 has a higher rating than Cat 5e. They all use RJ45 connectors and are usually interchangeable depending on the bandwidth requirements of your devices.

Question: What's the difference between UTP and STP? Are these cables shielded?
Answer: UTP stands for Unshielded Twisted Pairs. STP stands for Shielded Twisted Pairs. The ethernet standard uses data packet transmission and error correction. Unlike streaming data transmission, this standard simply buffers and repeats until it has a complete instruction set which compensates data transmission errors. Since UTP was cheaper in the beginning, it generally became the standard. If you are using the cables for ethernet connections, either should work. If you are using for a stream data system like video tranmission, the shielded should be used.

Question: What's the difference between "Solid" and "Stranded"
Answer: "Solid" vs. "Stranded" refers to the structure of the individual conduits in the cable. They can be a single solid wire or several thinner stranded wires. It's generally a matter of personal preferance which ones you use. Solids are easier to crimp connectors onto.

Question: What are the difference between the various in-wall ratings? (CMG, CMR, CMP)
Answer: In-wall ratings have to do with the burn characteristics of cabling and have no direct effect on the functional performance of the cables. CMG is for general in-wall use. It is equivalent to CL2 & CL3. It is for general commercial and residential in-wall installation applications. CMR is riser rated cable. These are suitable for situation where cable is passed from one floor of a structure to another. CMP is for Plenum and is the highest in-wall rating. Plenum cables are specifically designed to go into the Plenum areas of commercial building where air circulation systems are. Plenum cables are formulated so they do not produce toxic gases as they burn. While it is okay to use a higher rated cable in lower level applications, you should not do it the other way around.