old telephone cabling 4 wire rj 11 color code used in commercial and residence new
TRANSCRIPT
Old Telephone cabling4 wire
RJ 11Color code
Used in commercial and residence NEW
Prior to DivestitureIn years gone past, it was the responsibility
of the phone company not only to bring phone service to your house but to do the phone wiring within your house as well.
This is no longer the case. When you order phone service to your house, the local phone company installs a network interface device, a sturdy grey plastic box usually mounted either in your basement or on an outside wall.
ResidentialBefore Divestiture
Phone company maintained
AfterDemarcYou pay if the problem is
on your premiseStatement by operator
when calling in a trouble report “if the problem is internal you will need to cover the cost of the service call”
Note: Star and Branching
Typical Residential Layout
Wiring the NID
CommercialBefore divestiture
Teleco maintained all wiring Teleco repaired the phones
Afterinternal wiring turned over for $1Phones given to the campus
Demarc established Normally at the EF or Entrance Facility
FVTC – maintained on the 2nd floor
Commercial continuedTypical install
Large multi-conductor cable ran into DemarcRan into EF Entrance FacilityBackbone cables ran to TR’s Telecom Rooms or
IC’s Intermediate Cross ConnectsFrom TR’s to 110/66 blocks 110/66 cross-connect field to 110/66
Distribution fieldDistribution field to station jack or
Mutoas or connection points then to stationsIC’ to TR’s via a backbone cable
Jack to RackPrimary focus will be on the cable that runs
from the TR to the work area station jack.Performance testscable termination
110/66 blocksPatch Panels
Equipment Racks19” Rack standard23” Rack standard
GroundingNeed
Power companies do not provide groundSafety issues
BISCI Standards, Doc cam pg 292, 296
Typical facility layoutPG 9 BISCI – Doc camDraw on board
MDF
IDF
IDF
IDF IDF
STA
CO
Typical Residential layoutWire color code Telephone Network
InterfaceDraw on board
Function Old Color New Color
Tip 1 Green White/Blue
Ring 1 Red Blue/White
Tip 2 Black White/Orange
Ring 2 Yellow Orange/White
Multiple jacks in a residence
Plenum versus non plenum cablingWhyCharacteristics
Cable SpecificationsReview specs on a given cable – look up on
webhttp://docs.commscope.com/Public/5504LC.p
df
NEXT – Near end cross talk or EMI, signal transmitted on an adjacent pair from the near end and measured at the near end
FEXT – Far end cross talk, signal transmitted on an adjacent pair from the near end and measured at the far end of the cable
Attenuation This is the decrease in signal strength (expressed as negative dB) from one end of a cable to the other. The main causes of attenuation are impedance, temperature, skin effect and dielectric loss. Impedance is the combination of resistance, inductance and capacitance in a cable, it is measured in Ohms and opposes the flow of current.
DC loop resistance
This is simply the resistance between the two conductors of a twisted pair which is looped back at the far end. The primary purpose of this test is to make sure that there are no high resistance connections in the link.
Return Loss When a cable is manufactured there are slight imperfections in the copper. These imperfections all contribute to the Structural Return Loss (SRL) measurement because each one causes an impedance mismatch which adds to the cables attenuation.
Delay This is the propagation delay or the time it takes for the signal to travel from one end of the cable to the other
Delay Skew
The difference between the fastest and slowest pairs. Some networks use a four pair transmission method, this means that the signal is split into four, sent down the four pairs in the cable and re-combined at the far end. It is essential that the signals reach the far end at near enough the same time, otherwise the signal will not be re-combined correctly.
ACR
The pink area in the graph is the attenuation, and the blue area is the crosstalk.
ACR
The first thing to understand about testing data cables is the ACR, this stands for Attenuation to Crosstalk Ratio. The pink area in the graph is the attenuation, this can be caused by several things as will be explained below, and the blue area is the crosstalk. Attenuation is the reduction in signal strength over the length of the cable and frequency range
the crosstalk is the external noise that is introduced into the cable. So, if the two areas meet, the data signal will be lost because the crosstalk noise will be at the same level as the attenuated signal.
ACR is the most important result when testing a link because it represents the overall performance of the cable.
Toning out a cableTest Equipment Demo –click on imageGeneratorReceiver
Basic Telephone serviceSignals on a telephone line
Tracing a line, another set of test equipment
BatteryRingDial tone