STP: Shielded twisted pair
UTP: Unshielded twisted pair cable
Patchcord or Patch cable: A short length of stranded cable with a RJ-45 plug on either end, used to connect hardware to the Internet. Patchcords are also used to connect the Patch Panel to the Switch on the IT Closet end.
RJ-45: The popular name of the modular 8 pin connector used with UTP cable in structured cabling systems.
Jack: The receptacle for a RJ-45 Plug.
Multimode fiber: Multimode fiber cables have 2 different large diameter core sizes, 50 and 62.5 microns, allowing multiple pathways of light to pass through.
Singlemode Fiber: Single-mode cables have a small diameter 9-micron core allowing one pathway of light
LC Fiber Connector: LC stands for Lucent Connector or Little Connector and is a small form-factor Fiber optic connector that uses a 1.25 mm Zirconia ferrule
SC Fiber Connector: SC stands for Subscriber Connector and this is Square Connector that was developed by NTT (Nippon Telegraph and Telephone Japan).
MU Connector: MU is a small form factor SC.
ST Fiber Connector: ST stands for Straight Tip, a quick-release Bayonet style connector
Attenuation: The Data loss or the reduction in signal strength due to loss in the cable.
NEXT: Near End Cross Talk, or the signal coupled from one pair to another in UTP
Return Loss: Reflection from an impedance mismatch in a copper cable