1 / 83

Telephony Networking

Telephony Networking. Lesson 1: Telephony Essentials. Objectives. Describe the basic components of the telephone service Describe industry standards and protocols Identify the purpose and function of the central office Identify ways to connect to the central office

calix
Download Presentation

Telephony Networking

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. TelephonyNetworking

  2. Lesson 1:Telephony Essentials

  3. Objectives • Describe the basic components of the telephone service • Describe industry standards and protocols • Identify the purpose and function of the central office • Identify ways to connect to the central office • Identify various types of trunks and signaling methods • Explain various digital signal hierarchy terms and issues • Discuss SONET and SDH • Describe the purpose of the primary reference source • Describe the functions and uses of various types of telephone cable and wiring plans • List the common call-processing steps

  4. Telephony Basics • Basic telephone service consists of: • Public switched telephone network (PSTN) – a system of interconnected lines and switches • Plain old telephone service (POTS) – standard telephony wires that carry analog data • The last mile – the POTS portion of the PSTN that connects to a home or business (usually 2.5 miles) • The local loop – the tip and ring wire in the RJ-11 connector that provide a complete circuit to the central office • On-hook condition – the line is not busy and is ready for a connection • Off-hook condition – the line is busy

  5. Telephony Basics (cont'd) • Phone company terminology: • Local exchange carrier (LEC) – the local telecommunications company • Local access and transport area (LATA) – the area serviced by a LEC • Incumbent local exchange carrier (ILEC) – a telco already in business before the Telecommunications Act of 1996 • Competitive local exchange carrier (CLEC) – a company that competes with LECs and ILECs • Interexchange carrier (IXC) – a company that carries long-distance calls between LECs in different LATAs

  6. Industry Standards and Protocols • International Telecommunications Union (ITU) – manages worldwide telephony and networking standards • ITU-T series – standards documents labeledA through Z • Radio Equipment and Telecommunications Terminal Equipment directive – determines standards for wireless devices in the United Kingdom and Europe • Internet Engineering Task Force (IETF) – publishes Requests for Comments (RFCs) that provide information about standardized Internet protocols

  7. The Central Office • Central office (CO) – switching location for local and long-distance calls • CO uses three types of switches: • Class 3 (also known as an IXC, remote or long-distance switch) • Class 4 (also known as a tandem switch) • Class 5 (also known as an end-office switch) • Pulse Code Modulation (PCM) – converts analog voice data to digital format, then back to analog • PCM uses two compression algorithms: • Mu-Law (used only in North America and Japan) • A-Law (the standard for all international circuits)

  8. CO Connections • Point of presence (POP) – an interexchange carrier that connects long-distance services to a local connection • Foreign Exchange Service (FX) – provides telephone services from a CO that is outside the local calling area • Private Branch Exchange (PBX) – enables an organization to create in internal telephone-numbering system • Centrex – enables an organization to provide a pool of lines (alternative to PBX) • Direct Inward Dialing (DID)/Direct Dialing Inward (DDI) – enables multiple telephone numbers to be used on a few lines

  9. Trunks and Signaling • Trunk – a direct communication line between two switching systems; used to establish end-to-end communications between customers • Ear and mouth (E&M) trunks – carry voice and data on one series of lines, and signaling on a separate set of lines • Analog loop-start trunks – use two wires (the tip and the ring) to act as conductors for the connection • Ground-start trunk lines – require that both ends of a connection detect ground before the tip and ring wires can create a loop • Digital trunk lines – signaling information and data are sent digitally • A and B bits – signaling bits that allow a line to determine when connected systems check for dial tone and whether a remote system is in an on-hook or off-hook condition

  10. Digital Trunks and the Digital Signal Hierarchy • Digital signal hierarchy (DSH) – provides a standard for digital signal levels • Use DSH to purchase the required amount of network bandwidth to accommodate telephone and network connections • DSH levels are analogous to the T-carrier system • Digital signals use frames to carry data and addressing information: • Super frame • Extended super frame (the most common standard)

  11. SONET and SDH • Synchronous Optical Network (SONET) • High-speed, fiber optic networks organized in rings • Synchronous Digital Hierarchy (SDH) • Fiber ring networks used internationally • Essentially the same as SONET

  12. SONET and SDH (cont'd) The basic measure of SONET speed is the Synchronous Transport Signal level 1 (STS-1) frame, which travels at 51.84 Mbps

  13. SONET and SDH (cont'd) The basic unit for SDH is the Synchronous Transport Module (STM)-1 frame, which travels at 155.52 Mbps

  14. SONET and SDH (cont'd) Benefits of using SONET/SDH • You can use multiplexors and routers to combine different data lines and streams onto one line • One heterogeneous network can communicate with another distant heterogeneous network via one fiber optic ring

  15. The Primary Reference Source • Primary reference source (PRS) – a network of hyper-accurate clocks used to precisely time digital connections • PRS strata • Stratum 1 – extremely accurate but very expensive • Stratum 2 – used by long-distance providers • Stratum 3 – used by the CO • Stratum 4 – used by PBXs • Timing types • Asynchronous – no timing information is shared • Synchronous – a common system clock is used for all trunk lines and networks involved • Plesiosynchronous – a number of PRS clocks are used for all networks involved

  16. Cabling and Wiring • Service wire center – houses one or more local switching systems • Main distribution frame (MDF) – the main interface between the telco's lines and all internal lines • Patch panel – interconnects voice and data lines with RJ-11 and/or RJ-45 connectors • Intermediate distribution frame (IDF) – connects the MDF and a user's telephone handset • Combined distribution frame (CDF) – same as MDF and IDF but also houses connections from incoming lines and lines from inside equipment • Minimum point of entry (MPOE) – the point at which phone lines first enter your facility • Network interface device (NID) – terminates the connections from the central office • Load coil – device that improves voice transmission • Bridge tap – cable used to extend the loop

  17. Call-Processing Steps • Placing a call • Call setup – the connection is built between the local loop and the CO • Call connection maintenance – the connection is established and maintained • Call completion – breaking the connection • Common analog transmission impairments • Loss – parts of the transmission are dropped • Echo – parts of the conversation are repeated • Noise – unwanted energy that interferes with the signal • Crosstalk – parts of another conversation are heard • Echo cancellation in hybrid networks • When two-wire and four-wire networks are connected, a hybrid network is created, which can result in echo • An echo canceller balances the ohm levels between the lines, thereby eliminating the echo

  18. Summary • Describe the basic components of the telephone service • Describe industry standards and protocols • Identify the purpose and function of the central office • Identify ways to connect to the central office • Identify various types of trunks and signaling methods • Explain various digital signal hierarchy terms and issues • Discuss SONET and SDH • Describe the purpose of the primary reference source • Describe the functions and uses of various types of telephone cable and wiring plans • List the common call-processing steps

  19. Lesson 2:Investigating the Local Loop

  20. Objectives • Explain the importance of a demarcation point in telephony • Identify signaling types used in the local loop • Use numbering standards, including the North American Numbering Plan (NANP) and United Kingdom standards • Explain how the local loop is wired • Wire RJ-11 and RJ-12 connectors • Wire BT-431A and BT-631A connectors • Wire a wall jack and a line jack unit

  21. Inside the Demarcation Point • Minimum point of entry (MPOE) • The telco's demarcation point • The point where telco equipment ends and inside local loop wiring begins • Drop wire – the line from the telephone pole to the MPOE • Station wire – the line inside the MPOE

  22. Getting to the Local Loop • Global numbering plans • ITU Recommendation E.164 establishes standards for numbering plans • Telephone numbers should not exceed 15 characters • North American Numbering Plan (NANP) • Numbers are 10 digits long

  23. Getting to the Local Loop (cont'd) • Area code jeopardy and relief • Realignment – move areas from one area code to another • Split – create a new area code • Three-way split – create two new area codes out of one area code • Overlay – assign a new area code in the same geographic area as an existing area code • Specified Numbering Scheme (SNS) • Enables people in the U.K. to make calls using a uniform formula

  24. Signaling Types • Three types of signaling: • Rotary/pulse or multi-frequency (MF) – used on rotary dial phones • Dual tone multi-frequency (DTMF) – generated by touch-tone pads on all standard phones • Digital – does not process audible tones

  25. RJ-11 Connectors and Wiring

  26. RJ-11 Connectors and Wiring (cont'd) • Telephone jacks constitute a tip and ring • Tip • The "transmit" wire • The positive side of the circuit (in relation to the ring) • Ring • The "receiving" wire • The negative side of the circuit (in relation to the tip)

  27. RJ-12 Modular Connector

  28. RJ-11 Wall Connector Wiring

  29. BT-431A Connectors

  30. BT-631A Connectors

  31. Line Jack Units • Three types of line jack units • Master • PBX master • Secondary • Master line jack units contain: • A 26-amp surge protector • A 1.8 uf, 250-volt capacitor • A 470-ohm service resistor • Six terminals designed to accept wiring from the wall

  32. Wall Jack Wiring Diagram

  33. Summary • Explain the importance of a demarcation point in telephony • Identify signaling types used in the local loop • Use numbering standards, including the North American Numbering Plan (NANP) and United Kingdom standards • Explain how the local loop is wired • Wire RJ-11 and RJ-12 connectors • Wire BT-431A and BT-631A connectors • Wire a wall jack and a line jack unit

  34. Lesson 3:Infrastructure Issues and Standards

  35. Objectives • List common telephony connectivity and safety issues • Identify safety procedures • Explain safety standards • Determine the proper cabling procedures for specific environments • Identify various cable terminations • Wire an RJ-45 connector • Explain the importance of plenum cabling • Explain the necessity of securing equipment

  36. Common Telephony Issues • Quality assurance and business continuity • Uptime – the length of time a device has remained operational • Mean time between failure (MTBF) – the predicted amount of time a device will function before it requires maintenance or replacement • Return on investment (ROI) – the calculations made to ensure that equipment will result in company profitability • Telecommunications reliability and safety issues: • Extreme temperatures • Vibration and shock • Humidity • Fire • Noise • Altitude

  37. Common Telephony Issues (cont'd) • Electromagnetic compatibility • Electrostatic discharge (ESD) – An uncontrolled buildup of electrical current • Radio frequency interference (RFI) – A signal that causes another device to operate improperly • Electromagnetic interference (EMI) – interference produced by electromechanical devices • Solutions for electrical issues: • EMI suppression filters • Capacitors • Inductors • Line filters • Shielding • Ensuring proper humidity • Personnel safety concerns and procedures

  38. Network Equipment Building System • Network Equipment Building System (NEBS) • Protects people and property • Ensures operational continuity in the telephony industry • NEBS sets standards for the operation of telephony equipment with respect to: • Earthquake zones • Operating conditions and transport conditions • Levels of contaminants • NEBS standards documents • GR-63-CORE (Physical Protection) • GR-1089-CORE (Electromagnetic Compatibility and Electrical Safety)

  39. Standards Bodies Standards bodies provide telephony standards • Independent Committee for the Supervision of Standards of Telephone Information Services (ICSTIS) • International Organization for Standardization (ISO) • Independent Testing Laboratory (ITL) • European Telecommunications Standards Institute (ETSI) • Federal Communications Commission (FCC) • Telecommunications Industry Association (TIA) • Electronic Industries Alliance (EIA) • British Standards Institute (BSI)

  40. Proper Cabling Procedures When pulling cable: • Avoid sharp bends in the cable • Take care to eliminate sharp edges in conduits and other areas where cable might get worn or cut • Make sure that wiring does not interfere with mechanical equipment • Avoid passing wire close to fluorescent lights • Ensure that you are using the right type of cable for a particular job

  41. Choosing the Proper Cable • American Wire Gauge (AWG) standard • Standard gauges • 22 AWG – floor or wall cable • 24 AWG – backbone and drop cable • 26 AWG – drop cable and devices that pass data between similar devices (daisy chaining) • The EIA/TIA 568 standard is the most commonly used for twisted pair cabling

  42. RJ-45 connector – an eight-pin modular cable ending used in Ethernet networks Crossover cabling – allows two systems to communicate without the use of an intermediary device, such as an Ethernet hub IBM Cabling Standard

  43. Serial Cable Termination • Data terminating equipment (DTE) – a serial device that transmits and receives data digitally • Data communications equipment (DCE) – a device that is attached to a communications line and is capable of altering a signal in transit • RS-232 – a standard that enables DTE and DCE devices to communicate • Universal Asynchronous Receiver-Transmitter (UART) – translates parallel communication into serial • Additional ITU communication standards • V.24 through V.90

  44. PVC vs. Plenum Cabling • Plenum – the space above a dropped ceiling or behind a wall • UTP or STP cables have a polyvinyl chloride (PVC) jacket (emits toxic gas when burned) • When installing cable in a plenum: • Encase UTP or STP cable in a protective metal conduit • Use plenum cabling (has a Teflon jacket that inhibits burning)

  45. Securing Equipment • Physically secure telephony equipment using brackets • Isolate power sources by grounding them properly • PBX grounding: a steel rod 6 feet (2 meters) underground to which you attach the PBX ground lead

  46. Summary • List common telephony connectivity and safety issues • Identify safety procedures • Explain safety standards • Determine the proper cabling procedures for specific environments • Identify various cable terminations • Wire an RJ-45 connector • Explain the importance of plenum cabling • Explain the necessity of securing equipment

  47. Lesson 4:Troubleshooting

  48. Objectives • Identify common troubleshooting tools • Use a line test handset (butt set) • Use a tone and probe kit • Use a digital multimeter • Use a line tester • Discuss how to troubleshoot analog lines • Discuss how to troubleshoot digital lines • Discuss telephony power issues

  49. Short (continuity) Open (open fault) Terminator Cross Polarity Split Line imbalance Loopback testing End-to-end testing Troubleshooting Terms

  50. Troubleshooting Tools • Telephone line test set • Also called a butt set or handset • Used to test line quality • Used to check line polarity • Used to determine loss of current • End-to-end and loopback testing • A butt set is used to generate tones and frequencies to test lines • Can use analog butt sets to listen to digital communications by going into "data safe mode"

More Related