MBS Flashcards
Telecommunications wiring in buildings originally was?
Plain Old Telephone Service (POTS)
What is structured cabling?
A telecommunications cabling system that consists of a number of standardized smaller sub systems
3 categories of structured cabling?
Voice - Telephone, modem, fax
Data - LAN, MAN, WAN, personla computers
Video - CATV, CCTV, Skype
Where does the cabling begin?
Where the service provider terminates called the “Point of Demarcation” or “Demarc”
What are other names for Demarc?
Network Interface - NID
Node Zero
Telco Room
What is WAN?
Wide Area Network
What is LAN?
Local Area Network
What is MAN?
Metropolitan Area Network
The integration of various media (voice, video, data) on to a common medium (UTP, coax, fibre) is called?
Convergence
Internet Service Provider (ISP) wiring is typically provided by?
Twisted pair
Coax
Fibre
or Combination
Demarc point may include what devices?
Modems Routers Splitters Switches Cross Connects Control Panels Radios
LAN wiring generally refers to what kind of wiring?
CAT 5E, 6 or 6A UTP (but can be TP, coax or fibre)
Twisted Pair cable types?
Unshielded Twisted Pair (UTP)
Shielded Twisted Pair (STP) - each individual pair is shielded
Screened Twisted Pair (ScTP) - all pairs have an overall shield
Twisted pair cables carry ______ signals with ____ the signal on each conductor.
Balanced
Half
Twisted Pair TIP is _____ and the RING is ____.
Green
Red
The arrangement of linking networks is referred to as?
Topology
2 types of topology?
Physical - layout of devices
Logical - data transfer
6 basic topology networks?
Linear Bus Ring Star Mesh Tree or Expanded Star Hybrid (combo of different topologies)
Linear Bus topology advantages and disadvantages
Ad: Easily disconnect nodes w/o disrupting service
Dis: Not reliable…if trunk cable is down… everyone down
Star topology advantages and disadvantages
Ad: easy to add additional devices with no service interruption.
Dis: Hub represents a single point of failure… Not reliable
Ring topology advantages and disadvantages
Ad: performs better under heavy network load and the server does not need to manage connectivity to each device.
Dis: One bad workstation and the system is down. Making any changes will also affect network operation
Tree topology advantages and disadvantages
Ad: easy to add more nodes; reliable network and some level of redundancy with multiple servers.
Dis: Overall length of each segment is limited (100m), more difficult to wire than other topologies.
Mesh topology disadvantages
Expensive to have this if its a physical connection
Hybrid topology
A combo of different topologies (do not have a single point of failure and therefore are the most reliable)
Two types of protocol?
Ethernet
Token Ring
What is the 568 standard?
Allows installing the full cabling network without regard to its ultimate use
Cabling in a building can be divided into 2 sections?
Backbone
Horizontal
What is backbone cabling?
- (Vertical cabling) is the running of comm lines between floors or between buildings.
- Cables are consolidated at different points and then distributed through the building (telecommunication rooms).
- Fibre optic preferred.
What is horizontal cabling?
Cables run horizontally on each floor from the telecommunication room (100m max) (CAT 5E and 6)
What determines the characteristic impedance of a cable?
The dielectric insulation between the core and shield with its capacitance
These are the points where the cables are connected?
Cross Connects
What is the main cross connect?
Where the outside cables enter the building for distribution
Intermediate cross connects?
Used in large buildings to connect cables and then go out to telecommunication rooms.
What are horizontal cross connects?
where backbone cables meet horizontal cables, typically in close proximity to the work area
The _____ of a cable does NOT affect its impedance.
Length
_______ of the insulation DOES affect the impedance.
Distortion due to kinks, crimps etc.
The impedance is _________ dependant varying slightly over the intended frequency range.
Frequency
All components must have the same _________ or losses will occur.
Characteristic impedance
Radio transmitters and data modems are typically ____ohms or ____ohms and CATV systems are ____ohms
52 or 50 ohms
75ohms
The shield protects the cable from and provides a return path for?
Egressed (escaping) and ingressed signals and provides a return path for the signal.
The shield may be _____ or _____
Copper (92%) or Tinned Copper or Foil (100%)
Quad shielded coax has ________ for outstanding RFI immunity?
foil-braid-foil-braid
Double shielded cables have?
Both braided and foil shields
What is a Balun?
Balanced to unbalanced matching transformers
Which 2 bodies specify the “category” of cabling?
Electronics Industry Association (EIA)
Telecommunications Industry Association (TIA)
What is Power Over Ethernet (POE)?
44-57VDC (48V nominal) over our ethernet cabling
Used for phones, cameras, thermostats, remote data switches.
Types of communication systems?
Simplex
Half Duplex
Full Duplex
What is a decibel?
A ratio with a logarithmic scale. Sound level, voltage and power levels are often compared using dBs
What is thermal noise?
- Random electron movement through any conductive material (with resistance) creates random voltages at random frequencies.
Thermal noise is directly proportional to?
Temperature and has a flat frequency response
All frequencies with equal amplitude =
White Noise
Some amplifiers have a ____ adjustment to compensate and provide more GAIN at higher frequencies.
Slope
For analog systems the signal to noise ratio must be?
Very good or noise is noticeable
For digital systems SNR?
Can be lower b/c the receiver need only determine 1s from 0s
A very poor SNR results in a high ________ and causes signal _____.
Bit error rate
Dropouts/pixelation
If you add a splitter automatic gain control will _____
Increase
If you amplify the signal, automatic gain control will?
Decrease
Advantages of fibre optic cable
Speed Bandwidth Distance Immunity to noise Secure Lightweight Maintenance costs less
Most UTP cables have a _____ ohm impedance
100 ohm
UTP specs
- Most common cable used in DATA networking
- Each pair of wires is twisted together with a different twist rate (which cuts down on “crosstalk” btwn pairs)
- Typically #22 AWG Cu
- Impedance = 100ohms typically
Advantages and disadvantages of UTP?
Ad: Inexpensive, simple to install
Dis: Subject to interference, limited bandwidth (slower transmission)
Screened Twisted Pair specs
- Similar to UTP but with addition of a screen (foil) around all the pairs, to reduce noise
- Drain wire added to ground the foil better.
ScTP advantages and disadvantages
Ad: less interference from EMI
Dis: $$, harder to terminate
Shielded twisted pair specs
- Pairs are individually shielded for increase protection
- Allows higher bandwidth and longer distance than UTP and ScTP
Coaxial Cable specs
- Offers best high frequency performance of copper cables
- Share same centre axis
- Signal flows down the core and returns on the metallic shield
- Shield serves to confine energy within the cable
- Used for networks, CCTV, CATV
Coax cable advantages and disadvantages
Ad: familiar, easy to install, low attenuation, greater bandwidth, highly resistant to interference
Dis: Expensive, bulky, may one day be obsolete
RG-6 Coax specs
- Larger core
- Thicker insulation and 2-4 layers of shielding
- Used for digital signals, satellite TV, security cameras
RG-59 coax cable is the _____ for standard cable
Norm
Instead of using electronic pulses, fibre optic uses _____ pulses to transmit the same info.
Light
2 types of fibre optic cable?
Single Mode
Multi Mode
Single mode fibre cable specs
Narrow core (5.8 microns) Higher bandwidth for long distances (3kms) Less dispersion More expensive More difficult to terminate Uses laser for light source
Multi mode fibre cable specs
- Wider core (60 microns)
- Higher bandwidth for shorter distances (2km)
- More dispersion and therefore loss of signal
- In long runs multiple light pulses can distort and deliver incomplete date
- Uses LEDs as light source
25 Pair cable 5 tip colours?
White Red Black Yellow Violet
25 Pair cable 5 ring colours?
Blue Orange Green Brown Slate (grey)
What is an IDC?
Insulation Displacement Connector
- considered gas proof
POTS ____VDC on nominal hook, ___VDC off hook and ___-___VAC ringing voltage.
48
9
90-110
Wall mounted cabling symbols for voice/date, data and voice?
Voice/data = upside down triangle half black Voice = upside down triangle full black Data = upside down triangle white
Installation tips for cable pathways: Conduit
- Max length between pulls 100’
- Two 90 degree bends between pulls
- Ream the conduit
- Use insulated bushings at ends
- Conduits must have pull strings or ropes
- 40% conduit fill max
- Firestop material may be required
Installation tips for cable pathways: Cable Tray
- Max fill ratio 50%
- Access is important: 1’ above required
- Metal trays must be bonded to ground
Installation tips for cable pathways: Cable Placement
- Avoid kinking/over stretching
- Never loop cables; use figure 8s
- Use cable pulleys and lube
- Pulling tension = 25lb.ft max
- Bend radius (multi pair) 10x cable diameter
- Bend radius (horizontal) 4x cable diameter
- Never sliced damaged cables
- Leave strings on raceways
- Leave 18” at outlets and connection points
- Keep cables away from power sources (3” min)
When punching down twisted pairs untwist the conductors by ____ max for CAT5e and ____ max for CAT 6.
1/2”
1/4”
What is the most popular style of punchdown block?
110
What type of punchdown block is used when space is an issue?
BIX
What is the colour code for 8 conductor cable?
Blue Orange Green Brown (BLOGB) (Tip is white with colour and Ring is colour with white stripe)
2 types of cable testing?
Permanent Link
Channel
Permanent link testing
(Basic link) the cable from jack to jack (TR to workstation only)
Channel testing
Tests not only the cable but all hardware, patch cords and cross connect wiring… very extensive
569 cables must be less than ___m in the link and ___m in the channel and the length must be _____.
90m
100m
Tested
Cable length testing is done how?
- Done with a Time Domain Reflectometer AKA Radar
- Tester sends out a pulse, waits for an echo from the far end and measures the time it took for the trip.
- Knowing the speed in the cable, it calculates the length
All cable certification testers include a ____ to measure length.
TDR
Attenuation test
This test measures the signal loss from one end of the link to the other. (The smaller the dB number the better)
What is Crosstalk?
Unplanned transfer of data from one pair to another
Crosstalk test
- The larger the dB number the better, it means the signal is getting through
- Measured at both near end (NEXT) and far end (FEXT)
Attenuation to Crosstalk Ratio (ACR) test
- This is the measurement of how much more signal than noise exists in the link
- The larger the dB number the better
Fibre optic systems use _____ to transmit data from one location to another?
Light
What are the 4 main components of a fibre optic link?
- Transmitter
- Fibre optic cable
- Optical connectors
- Receiver
What is the bending of light called?
Refraction
What are 3 types of fibres used in optical cable?
- Glass
- Plastic-clad silica (PCS)
- Plastic
5 layers of a fibre optic cable?
- Core
- Cladding
- Coating
- Strengthening fibres
- Cable jacket
When installing large volumes of cables for backbone or horizontal, separate the cables into groups of ____-____ cables to minimize ______.
15-20
Cross talk
Wire mapping cable test
Help identify termination wiring errors. The test confirms whether or not there is proper connection of all 4 pair of UTP cabling.
A 3dB increase or decrease results in ______ or ______ the power.
Doubling
Halving
How can crosstalk be reduced?
- Twisting the wire
- Shielding the cable
- Physical separation during the manufacturing process
What are the 2 types of crosstalk?
Near end (NEXT) Far end (FEXT)
Near end cross talk refers to?
A transfer of signal between pairs at the end of the cable nearest the point of transmission
Far end cross talk refers to?
The signal level at the near end of the disturbed pair is compared to that transferred to the disturbed pair and measured at the opposite (far) end of the line.
What is delay skew?
The maximum difference in propagation time in all pairs of a cable
What is propagation delay?
It is the time required for the signal to travel from one end of the transmission path to the other
5 purposes of security systems?
- Deterrence
- Prevention
- Detection
- Response
- Apprehension
Most common home security systems have what 3 systems?
- Deterrence
- Detection
- Response
What is deterrence?
the ability to stop criminals from committing the acts they are considering
What is prevention?
Physically limits the perp, fences, locks etc.
What is Detection?
if they have ignored the first 2, now we need to detect, door contacts, motion sensors etc.
Response?
Alarm force, telus etc.
Apprehension?
Done by responding authorities, CCTV can aid
POE 8 position, 8 connectors are typically rated ____A per conductor.
1.3A
3 categories of Onion Skin Approach?
- Perimeter protection - door and window contacts, beam break.
- Space Protection - “back up” motion sensors.
- Spot protection - object protection, locks or wireless component fed to alarm system
What is the most secure security circuit?
Four wire ULC
What is the most common type of circuit used in intrusion alarm equipment?
Closed circuit
What are the four basic types of closed loop circuits?
- Two-wire
- Two-wire with EOL
- Four-wire
- Four-wire ULC
Two wire loop specs
Provide only partial supervision and are easily defeated
Two-wire with EOL specs
Very popular
Used for higher security
EOL is 1Kohms or 2.2Kohms
Will respond to both open and short circuit conditions
Four wire specs
AKA double-circuit or HI/LO loop
2 separate loops used one negative one positive
In secure condition there is no current flow between 2 loops
Supervises both shorts and opens
Four wire ULC specs
Highest level of security
HI and LO loop
Must be form C
When in alarm, HI loop opens and is also shorted to LO loop
Opens the HI loop and also provides a current path between the two loops
List 7 types of detection devices?
- Magnetic Contacts
- Passive infrared detectors (PIV)
- Microwave detectors
- Dual tech devices
- Photoelectric beam detectors
- Glass breaks
- Shock sensors
Magnetic contacts specs
- magnetically activated switch which is fixed to stationary frame and a magnet which is attached to moving part
- surface mount and recessed styles
PIR detector specs
- They detect changes in infrared energy in a space
- When senses a change, it drops its resistance causing a spike in current
- Extremely versatile
- 8’ standard mounting height
- Not ideal for high ambient rooms
Microwave detector specs
- Active motion detector
- 10-12GHz microwaves sent out and if no movement get same frequency back
- Movement will cause frequency to shift due to “Doppler Effect”
Microwave advantages
- Sensitive to motion toward detector
- Unaffected by ambient conditions
- More sensitive to low humidity
- Sensitive to room acoustics
Microwave disadvantages
- Subject to interference from other microwaves
- Sensitive to fluorescent lights, keep 2m away
- Must adjust range to not look for movement outside desired range
- Water flowing in pipes causes false alarms
Dual Tech Device specs
- Rely on 2 sensing methods which provide greater reliability
- Both sensors must detect movement for alarm
- Most are PIR/Microwave
Photoelectric beam detector secs
- Suitable for indoor and outdoor
- Two parts, transmitter and receiver
- If infrared beam is blocked alarm will signal
- Ranges up to 2000m
- Not fooled by other IR light sources, looking for signal that is pulsed and coded
- Not affected by ambient conditions
- Suitable for hazardous locations
Glass break detector specs
- Listen for the frequency of broken glass
- Wall or ceiling mounted
- Protect large areas
- Mount close to window trying to protect
Shock sensor specs
- Must be attached to window
- Detects shock waves
- Provides level of deterrence
Nurse Call central equipment
- the “brain” of the system
- houses all the programming and circuit boards, power supplies and terminal blocks
- normally located in an equipment room or closet
Nurse call patient station
- Wall mounted devices placed behind patient beds and allow them to summon staff for help
- Typically activated by call cord or pillow speaker
- When activated a call assurance light is activated and signal sent to annun panel
Nurse call annunciator panel
Located in nurse station, it signals the presence and location of all incoming calls or alarms
3 common incoming call types
- Code blue - 60PPM audible and visual, flashing red or blue light, high priority
- Toilet/Shower calls - 30PPM audible and visual, flashing white light, medium priority
- Patient station call - 6PPM audible, steady visual, white light, low priority
Nurse call duty station
installed in a location where nurses tend to be when they are not at the nurse control station or patient rooms, will have visual and audible indicators
Staff presence indicator station
Provide the input facility for the nurses and staff members to register their presence at specific location throughout facility
What electrical charac. allows us to use copper cladded steel center conductors successfully for high frequency signals?
Skin effect
What does RJ stand for?
Registered Jack
The dielectric of a coax serves two main purposes?
- Characteristic impedance
- Insulation
