• Coaxial (or coax) cables
• Twisted-pair cables
• Fiber-optic cables
• Serial cables

• Contains a center copper conductor surrounded by plastick jacket with a braided shield cover
• Good against EMI and RFI
• Plenum cables must be certified as flame retardant by the National Flame Protection Agency
• Thin Ethernet (Thinnet or 10Base-2): 1/4 inch coax cable (RG-58)
• Thick Ethernet (Thicknet or 10Base-5): 1/2 inch coax cable
• Requires BNC Connectors

1. Shielded Twisted-Pair (STP): multiple individually insulated wires that are twisted together in pairs with a metallic protection shield around them
2. Unshielded Twisted-Pair (UTP): twisted-pair cables without shielding

• Cat. 1: Used for POTS (Plain Old Telephone Service); two twisted pairs (4 wires)
• Cat 2, 3, 4: Obsolete (up to 10, 16 and 20 MHz).  4 pairs (8 wires)
• Cat. 5 and 5e (e=enhanced): common in modern networks, can handle Gigabit Ethernet. 4 twisted wire pairs (8 wires) at 100 MHz.
• Cat. 6: standard for new networks since 2002. 4 twisted pairs (8 wires) at 250 MHz.
• Cat. 6a (a=augmented): allows 10GBaseT at 500 MHz and up to 100 m

NBase=max transmission speed

X= several factors (e.g. max trasmission distance)

T=twist (twisted-pair)

EXAMPLE

100Base-TX

100Base=100 Mbps

T=twist

X= can mean different things

A Registered Jack (RJ) connector is used.

2 different RJ CONNECTORS:

1. RJ-45: Ethernet
2. RJ-11: POTS (and dial-up modems).

Transmits digital signals using light

PROS:

• Immune to EMI and RFI
• Trasmits up to 25 miles (40 km)

CONS:

• Difficult to install
• Expensive
• Harder to troubleshoot
• Troubleshooting equipment is more expensive than the one needed for twisted-pair test

1) Multimode Fiber (MMF): uses light to communicate the signal but light is dispersed on numerous paths as it travels through the core. A special material (cladding) helps line the core and focus the light back onto it.

FEATURES:

• For short distance
• Easy to work with
• Used in LANs

2) SINGLE-MODE FIBER (SMF): it's a single strand (or two strands) of glass fiber carrying the signal, created by LEDs (light emitting diodes) and laser, from end to end and pulsing it to create communication.

FEATURES:

• For long distance
• Hard to work with
• Used py phone companies and CATV companies

[image]

• ST (Straight Tip):

It uses a half-bayonette type of lock and a BNC attachment mechanism similar to Thinnet.

[image]

• SC (Square Connector):

It uses a push-pull connector similar to common audio and video plugs and sockets. A mechanism holds the connector in securely and prevents it from falling down (it's latched).

Convert from one media to another

Tipologies

• Single Mode Fiber (SMF) to Ethernet
• Multi Mode Fiber (MMF) to Ethernet
• Fiber to coaxial
• SMF to MMF

They transmit 1 bit at a time.

[image]

• RS-232 (RS= Registered Standard): older serial port, still used to connect to the console port of router and switches. Its connector is called DB-9. 

[image]

• USB (UNIVERSAL SERIAL BUS): built-in serial port on today's most motherboards. There are usually up to 4 external USB interfaces but add-on adapters can bring this number up to 6. USB can connect a mazimum of 127 external devices.

• Transmission speeds: common is 100 Mbps
• Distance: to the most is 328 ft. (100 m)
• Duplex (half-duplex: listen, then talk such as e.g. walkie-talkie; full duplex: talk and listen at the same time)
• Noise Immunity: fiber-cables are immune to electromagnetic interference (EMI) and more secure, because you can't tap into wire (i.e. intercept the message without cutting the wire).
• Frequency: the higher it is, the more bandwidth the cable can carry

Wiring standards

• 568A
• 568B
• Straight-through cable
• Crossover cable
• T1 Crossover cable
• Rollover

• 568A: Uses the green pair for pins 1 and 2 and the orange pair is split to pins 3 and 6, separated by the blue pair

• 568B: Uses the orange pair for pins 1 and 2 and the green pair for pin 3 and 6, separated by the blue pair 

[image]

 NOTE: neither of these standards uses pins 4,5,7, and 8.

Wiring standards (follows)

Straight-through cable

• Connects a computer to a hub, switch or router (pin 1 with pin 1, pin 2 with pin 2, etc.)
• It's 568B on both ends

Wiring standards (follows)

Crossover cable

Connects:

• computer to computer (pin 1 with pin 3, pin 2 with 6, etc.)
• network devices to network devices (switch to switch, hub to hub, host to host, hub to switch, router to host)
• 568A on one end and 568B on the other end.

T1 Crossover Cable

• Sometimes necessary when connecting to the internet.
•  Can connect more CSU/DSUs (Channel service unit/Data service unit: a layer 1 device connecting the serial ports on your router to the ISP's network point and that connects directly to the demarcation point).
  

Used to connect to a console port on a switch or router

Wiring Distribution Frame

• MDF (MAIN DISTRIBUTION FRAME): Reference point in a network, also considered as the WAN termination point, connecting to the outside world
• IDF (INTERMEDIATE DISTRIBUTION FRAME): connected to the IMF, is used to provide greater flexibility for the distribution of all the communication lines to the building. Floor devices are connected to it.

• 25-PAIR: cable formed by 25 individual wires used for phone cabling
• 110 BLOCK: it replaces phone installs and can be used with RJ-45 (network) or RJ-11 (phone) connections.
• DEMARCATION POINT (DEMARC): Last point of ISP's responsibility, usually located in the MDF.
• SMART JACK (or NETWORK INTERFACE DEVICE or NETWORK INTERFACE UNIT): special netwok device used between ISP's network and internal network.