Ethernet cable jacket rating comes in a variety of different types and materials. It's important to know the differences between cm, cmr and cmp cables because each different type is used is difference locations. In this blog post we'll do a quick break down on the big three networking cable jacket ratings.
CM rated cables are designed for general use. These are the types of cables that you usually see running from your computer to switch or wall port. These cables are most known as patch cords and come in stranded form. Stranded cm cables give them greater flexibility for the purpose of connecting short runs to your personal computer to server racks.
CMR cables, the R standing for riser, is more flame-resistant. These ones are more used to riser applications, hence the name, and are less used for patch cables. This means that they are usually run along bottoms or tops of walls and from the basement to the upper floor, so long as the cable does not need to run through an air duct.
CMP represents plenum cables. CMP are used for networking that must be done in air ducts or vents. Typically, CMP are used for offices or homes. For the latter, it is a practical application if the home network must be wired through ducts.
CMR cables are also used more for residential homes. These cables are less strict when it comes to fire requirements than CMP cables; CMR cables must pass a vertical burn test to prove that they can self-extinguish.
However, because CMR cables have less restrictions, CMP cables are typically more used, since they have to pass more regulations to be usable. However, CMR cables, when they can be used, are more flexible than CMP cables, making them easier to arrange in a room.