Types

Cat3 Plenum Cable
Cat3 cable plenum cable is shorthand for Category 3 cable plenum cable, which consists of unshielded twisted pairs, with varying numbers of the pairs.  Carrying a possible bandwidth of 16MHz, it is typically used for telephone lines today, but it was originally popular for 10Mb Ethernet until Cat5 came out. While Categories 1, 2, 4 and 5 are no longer supported, Cat3 has remained recognized by the standards. 

Cat5e Plenum Cable
Cat5e cable is an enhanced version of Cat5 cable, which is no longer supported by the standard associations.  It contains specifications for eliminating EMI that the original Cat5 did not have. Consisting of 4 twisted pairs, it is most often used for 100Mb Ethernet, though it can support up to 1 Gigabyte. 

Cat6 Plenum Cable
Cat6 is fast becoming the new standard for Ethernet and is meant for Gigabit networks. Similar to how Cat5e has specifications for eliminating EMI, Cat6 has even more, which makes the signal even stronger. It also has just 4 twisted pairs, and its base rating is for 250MHz, for 1000Mb Ethernet (1 Gigabyte).  Cat6 is also backward compatible and can be used for an application that calls for Cat5e.

Fire Alarm & Security Plenum Cable (FPLP) – Shielded and Unshielded
FPLP cable is manufactured for use in power limited fire alarm systems, burglar alarms and smoke detectors. The term FPLP is the standard code from the NEC. A power limited circuit has a limited amount of power supplied to it, which minimizes the damage a short circuit or fault could inflict. These specific types of power-limited cables are meant for use with fire alarm and security systems, because certain protection needs to be applied as they are very important systems. 

Unshielded Multi-Conductor Plenum Cable
An unshielded multi-conductor plenum cable can have any number of conductors depending on the needs of the customer.  The conductors themselves could also vary in AWG as well. AWG stands for American Wire Gauge, and is the standard measuring increment for wire. 

There are several different applications that unshielded multi-conductor cables can be used for.  Intercom systems, audio systems and power-limited circuits are a few of these.  They come in either Class 2 or Class 3 NEC standardized varieties. 

Shielded Multi-Conductor Plenum Cable
A foil-shielded multi-conductor cable is much like its unshielded counterpart in that it can have several different numbers of conductors and AWG sizes. The major difference is that it contains a foil shield, which helps to guard against electromagnetic interference (EMI).  It is also used for the same applications as the unshielded version: intercom systems, audio systems and power-limited circuits are a few of these. It just has the added shield protection.

Shielded Multi-Paired Plenum Cable
A foil-shielded multi-paired plenum cable has a number of twisted pairs that are covered by a foil field protecting them from EMI.  These cables can also vary in AWG sizes and number of twisted pairs depending on their eventual purpose. They are generally used for remote control circuits, power-limited control circuits and process control. While the multi-conductor types are rated for 150V, foil-shielded multi-paired cables are rated for 300V. 

Mid-Cap Shielded Multi-Paired Plenum Cable
Mid-Cap stands for mid capacitance. Capacitance is defined as the ability of a material to hold a charge. As the current flows through a cable, current can be lost to surrounding objects because electrical fields can form that can trap energy.  The foil shield helps stop this from happening.  High capacitance means that more of the charge is held in that electrical field.  Mid capacitance means that less of the charge is held and more of the signal makes it through the cable. Mid cap shielded multi-paired cables are used for remote control circuits, power limited circuits and process controls.

Low Cap Shielded Multi-Paired Plenum Cable
Low Cap stands for low capacitance. In the same realm that mid cap is better than high cap, low cap is even better.  Significantly more of the signal makes it through the cable than a cable without capacitance protection. These cables are generally used for remote control circuits, power limited circuits, process controls and any application calling for low capacitance.

Individually Shielded Multi-Paired Plenum Cable
These cables have sets of twisted pairs, and instead of a single foil shield that covers all of the pairs, each set has a foil shield around it.  This is useful for when the separate conductors need to be protected from each other as well as from the outside.  Individually shielded multi-paired plenum cables are also used for remote control circuits, power limited circuits and process controls, as well as point of sale systems.