C3. Your favorite cables Flashcards

1
Q

What is the coax cable? How is it constructed? What is it made of?

A

Coax stands for coaxial; It has a center conductor made of copper and an outer plastic jacket with a braided shield over copper

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2
Q

What kind of plastic is used for coax cables (and where is it used?)

A

PVC vs FEP; FEP is just good old teflon. Teflon is a plenum-rated coating; good replacement for all other media because it’s safe in case of fire

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3
Q

What is one example of a coax cable?

A

Thinnet - thin ethernet - is a thin coaxial cable; Thinnet is used with the BNC connectors on both sides…

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4
Q

What are the BNC connectors?

A

BNC babies are a kind of coaxial connectors

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5
Q

What type of coaxial connectors are used on cable TV?

A

F-type

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6
Q

What’s a twisted pair cable? What are the two kinds of twisted pair cables?

A

A cable with … deep breath! multiple!! twisted pairs. There are two kinds of cable - STP and UTP; some are shielded - hence a shielder twisted pair or STP. Some are unshielded - UTP.

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7
Q

Why is UTP so popular? Where is it used?

A

UTP is used in Ethernet cabling!

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8
Q

What is crosstalk?

A

Crosstalk is a kind of interference that occurs when electromagnetic signals are conducted on copper wires in close proximity to one another; the interference is minimized by twisting the cables together

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9
Q

What are twisted pair cables good for?

A
  1. They’re cheaper than other types of cabling
  2. They’re easy to work with
  3. They allow transmission rates that were impossible 10 years ago
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10
Q

What is category 1 of twisted wire pairs? What’s its conventional name? What kind of signal frequency range does it support?

A

Two twisted wire pairs (2^1 lol) POTS - plain old telephone service; it supports signals limited to 1 MHz frequency range

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11
Q

What is category 2 of twisted wire pairs? What kind of speed and signal frequency range does it support?

A

Four twisted wire pairs. This category handles transmissions up to 4 Mbps, with a frequency limitation of 10 MHz

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12
Q

What is category 3 of twisted wire pairs? What kind of speed and signal frequency range does it support? What is it used for?

A

Four twisted wire pairs, three twists per foot. This category handles transmissions up to 10 Mbps and 16 MHz
It’s used in telecommunication equipment and is totally obsolete for networks

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13
Q

What is category 4 of twisted wire pairs? What kind of signal frequency range does it support?

A

Four twisted wire pairs. Up to 20 MHz. Obsolete

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14
Q

What is category 5 of twisted wire pairs? What kind of cable is it used for? What kind of signal frequency range does it support?

A

Four twisted wire pairs; used for 100BaseTX; rated for 100 MHz

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15
Q

What is category 5e of twisted wire pairs? What kind of cable is it used for? What kind of signal frequency range does it support? What’s special about it!

A

Has four twisted wire pairs; recommended for 1000BaseT; rated for 100 MHz
It’s capable of handling disturbance on each pair that’s caused by transmitting on all four pairs at the same time - so we can use it with Ethernet - and this is the lowest category good for Ethernet!

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16
Q

What is category 6 of twisted wire pairs? What kind of cable and signal frequency range does it support?

A

Four twisted wire pairs, used for 1000BaseTX and rated for 250 MHz.

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17
Q

What is category 6A of twisted wire pairs? What kind of speed and signal frequency range does it support?

A

Four twisted wire pairs, used for 10GBaseT for up to 100 meters; rated for 500 MHz.

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18
Q

What is category 7 of twisted wire pairs? What is the speed that it supports and across what distance does it support it?

A

Four twisted wire pairs; Allows 10 Gigabit internet over 100 meters of copper cabling

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19
Q

What kind of connectors typically go with twisted pair cables?

A

RJ - registered jacks!

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20
Q

Name the three kinds of RJ connections and what they are good for

A

1) RJ-11 for phones
2) RJ-45 for LANs with short distances
3) RJ-48c for T1 connections

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21
Q

Describe the fiber-optic cables - how do they essentially transmit signals? What are the two kinds of transmission (but not two types of cables)?

A

They transmit digital signals using eight impulses rather than electricity; light impulses are carried on either glass or plastic core

  • Glass core is better for distance
  • Plastic is better for … cost, of course :)
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22
Q

What are the two kinds of fiber-optic cables?

A

SMF and MMF - single-mode fiber and multi-mode fiber! the difference between SMF and MMF is in the number of rays they carry

23
Q

What are the pros of fiber-optic cables?

A

Are completely immune to EMI and RMI; can transmit across up to 40 km

24
Q

Describe SMF fiber optic technology! And what’s SMF again?

A

SMF = single mode fiber; They support very high-speed long-distance media that consists of 1-2 fiber strands.
They use LED and laser as their main light source
Light is transmitted end to end through the cable and pulsed - and are superfast! Ultrafast! Just wow kind of fast!

25
Q

What are the cons of fiber-optic cables?

A

FO is difficult to install; also, it’s more expensive than twisted pairs. Troubleshooting is obviously also more expensive and more difficult than with twisted pairs

26
Q

Describe MMF fiber optic technology! And what’s SMF again?

A
In MMF (multi mode fiber), light is transposed on numerous strands as it travels through the core and back.
- MMF cladding lines the core and focuses the light back on!
27
Q

Give me five kinds of FO connectors!

A
APC - angled physical contact 
UPC - ultra physical contact
ST - straight tip
SC - subscriber connector
FC - field connector
28
Q

What’s cool about APC? And what IS APC?

A

APC is an angled physical contact - a type of fiber optic connector. It has very little db loss, yay!

29
Q

What’s cool about UPC? And what IS UPC?

A

UPC - ultra physical contact - a type of fiber optic connector where light is reflected to the core of the cable, because the angled connector causes light to reflect back to the cladding. Which, unfortunately, leads to quite a bit of the DB loss

30
Q

Describe an SC and remind yourself the old lady what it is

A

SC = subscriber connector; a type of FO connector; it’s latched and durable. That’s basically it

31
Q

Describe an ST and remind yourself the old lady what it is

A

ST = straight tip connector; it uses a BNC attachment mechanism and it is easy to attach and disconnect

32
Q

Describe an FC and remind yourself the old lady what it is

A

FC = field connector; it’s used in telecommunications and measurement equipment with single-mode lasers

33
Q

What are FDPs?

A

FDPs are termination and distribution systems for fiber optic cable facilities

34
Q

What are fiber optic transceivers? How do you characterize transceivers in terms of their directionality?

A

transceivers are devices that are both transmitters and receivers; they can be simplex (unidirectional) or duplex

35
Q

What are the two kinds of fiber optic transceivers? Where are they used?

A

SFP+ and QSFP
SFP - Small Form-factor Pluggable; it’s a compact hot-pluggable optical module transceiver used for telecommunications and data comm application
QSFP is a compact hot-pluggable transceiver used for data communications applications

36
Q

What are the four kinds of FO media converters?

A

SMF to Ethernet, MMF to Ethernet, fiber to coax, SMF to MMF

37
Q

What are the two kinds of small form factor connectors used in fiber optic stuff? What are they good for?

A

MTRJ and LC

  • MTRJ is a mechanical transfer registered jack. has many benefits!
    1) easy to use
    2) TX and RX strands in one connector!
    3) smol and compact
    4) keyed for single polarity (only god knows what this means lol)
  • LC is a local connector. it’s popular with fibre-channel adapters. it’s used for fast storage area networks and with gigabit ethernet adapters
38
Q

What’s a popular standard for cables with serial data signals, you ask? What’s a popular connector used for RS-232 cables?

A

RS-232. Mysteries….

DB-25 connector.

39
Q

What’s a USB?

A

Universal Serial Bus….

40
Q

What are the five key properties of cables? Just name them, at most give a concise overview

A

1) Transmission speeds - from 100 Mbps to 10 Gbps
2) Distance; we’ve got a notion of attenuation here - degradation of speed due to the medium and the distance that signals have to travel
3) Full vs half-duplex - in full duplex devices and concurrently send and receive communication, and half duplex is about doing only one thing at a time
4) Noise immunity - whenever electrons go through a cable, we’ve got a magnetic current, which brings up two issues - (a) wire tapping - people can read messages without cutting the cable (go for fiber-optic to be safe) (b) wires can take on additional current if they are near a source of magnetism
5) Frequency

41
Q

What are T568A and T568B wiring standards?

A

They differ by how we connect certain cables; I’ll need to stick in a diagram here…

42
Q

Straight-through cables connect ____ standards and crossover cables connect ______ standards

A

T568A with A’s and B with B’s;;

crossovers just cross the two!

43
Q

What devices do straight-through cables connect>

A

Hosts with switches, hub/router + hub/switch

44
Q

What devices do crossover cables connect?

A

Switch + switch, hub + hub/switch, host + host/router

45
Q

Describe a UTP Gigabit wiring

A

Here, we use four wire pairs and rather advanced electronics so that each pair on the cable can do simultaneous transmissions

46
Q

What does a rolled/ rollover cable connect?

A

It connects a host [EIA-TIA 232] interface to a router COM (console serial communication) port

47
Q

What does T1 Crossover cable help to determine?

A

T1 crossover is a sort of connection that determines our choices of serial cables! if a T1 is built into the router then we’ll use an Ethernet cable
T1 crossover cable is also needed between two CSU/DSU

48
Q

What is an MDF/IDF unit?

A

It’s a sort of wiring point used as a reference for phone lines. It’s also a WAN termination point. MDF = main distribution frame and IDF = intermediate distribution frame. MDF connects to IDF and provides greater flexibility for the distribution of communication lines to the building
- IDF - just another wire frame; it’s typically located in an equipment or telecommunication space

49
Q

What’s a 66-block wiring?

A

It’s a kind of wiring that uses a 25-pair cable and is (has?) a standard termination block

50
Q

What’s a 110-block wiring?

A
  • It’s a kind of wiring that replaced most phone wire installations
  • it’s used a great deal with computer networking
51
Q

What’s a demarc?

A

It’s an RJ-45 jack that a CSU/DSU connects from a router to a WAN; this is where sysadmins start checking when troubleshooting connectivity

52
Q

What’s a smart jack?

A

It’s a network interface device; a special interface used between the service provider’s network and the internet network

53
Q

What’s a demarc/demarc extension?

A

The length of copper/fiber that begins after the demarc but still doesn’t reach all the way up “to your office”