3.1 – Cables and Adapters: Network Cables

Network Cabling Types

• Network cabling is crucial for global communication; correct choice is vital for new installations.
• Wired networks still dominate, despite widespread wireless use, mainly ethernet twisted pair copper cables.
• Twisted pairs are essential for minimizing interference and enabling signal transmission.
• Four pairs of twisted wires with different colors exist inside ethernet cables (blue, blue/white, green, green/white, orange, orange/white, brown, brown/white).
• Wires carry equal and opposite signals (transmit plus/minus). Twists in the cable mitigate interference.
• Signals at the receiving end are compared, identifying and correcting interference due to twisting at differential rates.
• Cable categories (e.g., Cat5, Cat5e, Cat6, Cat6A) have different electrical properties and support various network speeds. They are defined by IEEE standards with minimum requirements.
• 1000BASE-T (1 Gbps) uses Cat5/5e; 10GBASE-T (10 Gbps) uses Cat6/6A, often 100m max. Cat5e is more common now, although older networks may use Cat5.
• Cat6A is an augmentation of Cat6.
• Coaxial cables (e.g., RG6) are common for cable TV/internet and are characterized by a single wire conductor, an insulator, metal shielding, and a plastic jacket.
• Plenum cables are crucial in shared airspaces (plenum) to mitigate fire hazards, ensuring smoke/toxic fumes aren't distributed during fires that are designed to have low smoke and non toxic emissions in the case of fire. PVC is often used for non-plenum cables; FEP (fluorinated ethylene polymer) is for plenum-rated cables.
• UTP (Unshielded Twisted Pair) is the most common type, lacking external shielding.
• STP (Shielded Twisted Pair) offers enhanced protection against interference.
• Cable markings (e.g., U/S/F/TP) indicate shielding types (e.g., U for unshielded, S for braided, F for foil).
• Direct burial STP cables are specifically designed for outdoor use, incorporating waterproofing and gels to resist moisture.
• Direct burial cables often contain a drain wire to minimize voltage issues.

Cable Construction Details

• Shielded twisted-pair cables utilize waterproofing gel and shielding around individual pairs and entire cable.
• Cable markings are crucial. The standard format is <Shielding Type>/<Shielding Type><Twisted Pair>. For instance, F/UTP, implying a foil shield around the entire cable, and no shield around the individual pairs, or S/FTP implies a braided shield around the entire cable and a foil shield around each wire pair.