The Telephone Network

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The Telephone Network
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The Telephone Network
The Telephone Network Objectives

• Chapter 3 Objectives
• Explain how the telephone network is laid out
• Discuss the differences between the various
  office functions used in the hierarchy
• Describe the different names applied to the
  various carriers in the network
• Describe the basis for the local loop
• Explain the pieces used to connect to the
  customer location
• Openly recognize the problems associated with the
  local loop connections and the impairments that
  can occur
• Recognize the difference in the North American
  Numbering Plan and discuss the problems being
  poised now
• Explain why we are running out of numbers today

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The Telephone Network
The Telephone Network Terms

• Terms
• network
• demarc then and now
• who is the owner inside and outside?
• local loop
• Topology of connections
• Pairs of wires
• 2-4-8?voice, fax, data?
• xDSL
• Central office to the business/residence
• Star, ring configuration
• Wire center
• Frame, switch, routing decisions
• Links to other switches, interoffice trunks

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The Telephone Network The Local Loop

• Local loop
• One pair of wires or equivalent
• Party line
• Outside plant
• Lateral distribution
• Station drop
• Aerial, underground feed, direct burial

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The Telephone Network
The Telephone NetworkTypes of Communications

• The Local Loop

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The Telephone Network Network Hierarchy

• Pre-1984
• ATT and BOCs most of the network
• Five-level architecture based on call completion
• Trunks between offices
• Wire, coax, radio, fiber optics
• Class 5 end office, closest to the customer
  (19,000)
• Class 4 toll center or tandem (940)
• Class 3 primary center (170)
• Class 2 sectional center (50)
• Class 1 regional center (10)

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The Telephone Network
The Telephone NetworkTypes of Communications

• Network hierarchy pre- 1984

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The Telephone Network Network Hierarchy

• Post-1984
• Separation of BOCs from ATT
• Call completions continued network intact
• Terms and connections
• LEC, ILEC, RBHC
• ICEC, IXC connections to BOC
• Equal access, digits, complexity
• Conforming, non-conforming offices
• POP
• Public-Switched Network
• PSTN
• Goal complete the call (shortest of quickest)

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The Telephone Network
The Telephone NetworkTypes of Communications

• Tandem (Class 4) arrangement

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The Telephone Network
The Telephone NetworkTypes of Communications

• Network after divestiture

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The Telephone NetworkNorth American Numbering
Plan

• NANP 10 number-based
• Area code, N11
• 640 new codes, depleted 2005 to 2010
• Worldwide shortage
• Exchange code
• NNX, NXX
• Subscriber extension 2,3,4 more numbers?
• 10 or 11 numbers for local connection
• Private networks (owned equipment)
• Hybrid networks
• Local Access and Transport Areas (LATAs)
• Intrastate-Intra-LATA LEC
• Intrastate-Inter-LATA IEC
• Interstate-Inter-LATA IEC
• Interstate-Intra-LATA either/or
• Telecommunications Act of 1996

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The Telephone Network
The Telephone NetworkTypes of Communications

• Private Network

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The Telephone Network
The Telephone NetworkTypes of Communications

• Hybrid Network

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The Telephone Network Wiring Connections

• Hooking things up
• Two, four wire
• 66 block or RJ-21X
• RJ-11C or RJ-12
• RJ-45X
• RJ-48X
• RJ-68 (smart jack)
• USOC

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The Telephone Network
The Telephone NetworkTypes of Communications

• Basic forms of communications channels
• Simplex
• Half Duplex
• Full Duplex

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The Telephone Network
The Telephone Network Equipment

• Connections and functions list (sample)
• Single line set
• Multiline set (key set)
• PBX (private branch exchange)
• Modem (data communications over analog network)
• Multiplexer (many users or conversations on
  single line)

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The Telephone Network
The Telephone NetworkTypes of Communications

• Connections and functions list (sample)
• ACD (automatic call distributor)
• VMS (voice mail system)
• Radio systems
• Cellular telephones
• Facsimile machines
• Centrex (central office exchange)

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The Telephone Network
The Telephone NetworkTypes of Communications