Presentation on theme: "Old Telephone cabling 4 wire Used in commercial and residence NEW"— Presentation transcript:
1Old Telephone cabling 4 wire Used in commercial and residence NEW RJ 11Color codeUsed in commercial and residence NEW
2Prior 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.
3Residential Before Divestiture After Phone company maintained Demarc You 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
6Commercial Before divestiture After Demarc established Teleco maintained all wiringTeleco repaired the phonesAfterinternal wiring turned over for $1Phones given to the campusDemarc establishedNormally at the EF or Entrance FacilityFVTC – maintained on the 2nd floor
7Commercial continued Typical 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 blocks110/66 cross-connect field to 110/66 Distribution fieldDistribution field to station jack orMutoas or connection points then to stationsIC’ to TR’s via a backbone cable
8Jack to RackPrimary focus will be on the cable that runs from the TR to the work area station jack.Performance testscable termination110/66 blocksPatch Panels
9Equipment Racks19” Rack standard23” Rack standard
10Grounding Need BISCI Standards, Doc cam pg 292, 296 Power companies do not provide groundSafety issuesBISCI Standards, Doc cam pg 292, 296
14Plenum versus non plenum cabling WhyCharacteristics
15Cable Specifications Review specs on a given cable – look up on web
16NEXT – Near end cross talk or EMI, signal transmitted on an adjacent pair from the near end and measured at the near endFEXT – Far end cross talk, signal transmitted on an adjacent pair from the near end and measured at the far end of the cableAttenuation 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.
17DC 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
18Delay SkewThe 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.
19ACRThe pink area in the graph is the attenuation, and the blue area is the crosstalk.
20ACR 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
21the crosstalk is the external noise that is introduced into the cable 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.
22Toning out a cable Test Equipment Demo –click on image Generator Receiver
23Basic Telephone service Signals on a telephone lineTracing a line, another set of test equipmentBatteryRingDial tone