Phone Systems
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Phone Systems

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Phone Systems Phone Systems Presentation Transcript

  • Phone Systems Overview of Communication Matthew Whited
  • Brief History
    • 1840: Samuel F.B. Morse & Alfred Vail were granted patent for first practical telegraph
    • 1876: Alexander Graham Bell was granted patent for telephone
    • 1877: Bell offered to sell telephone to Western Union for $100,000
    • 1885: AT&T formed as a subsidiary of American Bell
    • 1893: Heinrich Hertz, detected first radio waves
    • 1896: Guglielmo Marconi invented the radio
    • 1912: Lee de Frost invented the vacuum tube
    • 1924: H. Nyquist developed the “telephotography” machine
    • 1946: First Mobile Phone Call (AT&T)
    • 1947: William Shockley, John Bardeen, and Walter Brattian invent the transistor
    • 1960: First Communication Satellite “Echo 1” (Passive Reflector / NASA)
    • 1960: First Active Repeater Satellite “Courier 1B” (Philco)
    • 1962: First Private Funded Communication Satellite “Telstar” (AT&T)
    • 1973: Martin Cooper invents first personal mobile handset
    • 1988: TDMA is developed by CTIA (Cellular Technology Industry Association)
  • Brief History
  • Brief History Echo 1 (NASA)
  • Brief History Courier-1A Telstar
  • Media
    • Interfaces
    • Analog
    • Digital
    • Cellular
    • Switching
  • Interfaces
    • Standards Groups
    • RJ (Registered Jack)
    • OC (Optical Carrier)
    • RS (Recommend Standard)
  • Standards Groups
    • USOC (Universal Service Order Code)
    • ANSI ( American National Standards Institute)
    • EIA ( Electronic Industries Alliance)
    • TIA (Telecommunications Industry Association)
    • ISO (International Standards Organization)
    • IEEE (Institute of Electrical and Electronics Engineers)
    • ITU (International Telecommunication Union)
    • CCITT (International Telegraph and Telephone Consultative Committee| Comité consultatif international téléphonique et télégraphique)
    • OSI (Open Systems Interconnection)
  • RJ (Registered Jack)
    • http://www.arcelect.com/RJ_Jack_Glossary.htm
    • Indicator Letters
      • C: Flush Mount
      • W: Wall Jack
      • S: Single Line
      • M: Multi-line
      • X: Complex-Line
    • RJ-11C/W: Standard Phone Jack
      • 6 or 4 pin, 3 or 2 pair
      • Pin 3/2: Ring
      • Pin 4/3: Tip
    • RJ-12C/W
      • 6 pin, 3 pair
      • Pin 3: Ring
      • Pin 4: Tip
    • RJ-45C/W
      • 8 pin, 4 pair
    • RJ-48X (SmartJack)
      • T1
  • RJ (Registered Jack)
  • OC (Optical Carrier)
    • OC-n Mbps = n x 51.8Mbps
    • SONET (Synchronous Optical NETworking)
    • OC-1: 51.8Mbps
    • OC-192: 9945.6 Mbps
  • RS (Recommended Standard)
    • DTE (Data Terminal Equipment)
    • DCE (Data Communication Equipment)
    • RS-232 a.k.a. EIA323 / TIA232
      • Revision “C” set in 1969
      • Point to Point
      • Standard Serial Interface on a Computer
    • RS-485 a.k.a. EIA485 / TIA 485
      • Point to Multi-Point
  • RS (Recommended Standard)
  • Analog
    • POTS (Plain Old Telephone Service)
    • PSTN (Public Switched Telephone Network)
    • Tip/Ring
  • Analog
  • Digital
    • Frame Relay / X.25
    • Leased / Dedicated Lines
    • ISDN (Integrated Services Digital Network)
    • T/E Carriers
    • ATM (Asynchronous Transfer Mode)
  • Frame Relay / X.25
    • Packet Switching Network
    • Virtual Circuits
    • Connects to a semi public cloud or “Frame”
    • Typically pay for usage
    • Typically configured as Point to Multi-Point
    • Slower then dedicated service
  • Leased / Dedicated Lines
    • Point to Point
    • Typically pay for mileage (tariffs)
  • ISDN ( Integrated Services Digital Network)
    • B: Bearer 64k (Data or Voice)
    • D: Data 16k (Control)
    • Can be Channelized
    • PRI (Primary Rate Interface)
      • T1: 23B+D (US/Japan)
      • E1: 30B+2D (Everyone Else)
    • BRI (Basic Rate Interface)
      • 2B+D
  • T/E-carriers
    • DS (Digital Signal)
      • DS0: 64kbps
      • T1: DS1 = DS0 x 24
      • T2: DS2 = DS0 x 96 or DS1 x 4
      • T3: DS3 = DS0 x 672 or DS1 x 28
      • T4: DS4 = DS0 x 4032 or DS3 x 6
      • E1: DS0 x 32
      • E2: DS0 x 128
      • E3: DS0 x 512
      • E4: DS0 x 2048
  • ATM (Asynchronous Transfer Mode)
    • Uses TDM and PCM
    • Cells instead of frames
      • Reduced jitter caused by multiplexing
  • VoIP (Voice over Internet Protocol)
    • NVP (Network Voice Protocol)
    • NBX (Network Branch Exchange)
    • SIP (Session Initiation Protocol)
    • H.323
    • IAX2 (Inter-Asterisk eXchange)
    • SCCP (Skinny Client Control Protocol)
  • NVP (Network Voice Protocol)
    • 1973 by Danny Cohen for ARPAnet
    • Outdated
  • NBX (Network Branch Exchange)
    • 3Com
    • POSIX (Real-time Embedded UNIX)
    • Layer 2 Protocol
    • Can ride inside of IP Packets
  • SIP (Session Initiation Protocol)
    • Industry Standard
    • Allows use though 1 firewall
    • TCP and UDP ports 5060
  • H.323
    • Example is Microsoft Netmeeting
    • Directly Support Video
    • Doesn’t like firewalls much
  • IAX2 (Inter-Asterisk eXchange)
    • Mark Spencer
    • Proprietary but Open
    • Low overhead
    • Designed with NAT and Firewalls in mind
    • Designed with Trunking and Multiplexing in mind
    • UDP 4569
    • Based on SIP, MGCP, RTP
  • SCCP (Skinny Client Control Protocol)
    • Cisco
    • Windows Server
  • Cellular
    • Voice
      • Analog
      • Digital
        • TDMA (Time division multiple access)
        • CDMA (Code division multiple access)
        • GSM (Global System for Mobile Communications)
    • Data
      • GPRS (General Packet Radio Service)
      • EDGE (Enhanced Data rates for GSM Evolution)
  • Cellular Hide a Cell Tower
  • Switches
    • Store and Forward
      • Buffers transmission
      • May run checksum
    • Cut Through
      • Read only enough of the data stream to identify receiver
    • Fragment Free
      • Form of Cut though that checks that the receiver is available
    • Adaptive
      • Can automatically pick best method of switching for data stream
  • Plexes
    • Simplex
      • Paging Systems
      • Unidirectional
    • Half Duplex
      • PTT (Push To Talk)
      • One Direction at a time
    • Full Duplex
      • Phone
      • Both Directions at the same time
  • Encodes
    • Analog to Digital
    • TDM (Time-Division Multiplexing)
      • 64Kbps x 24 Channels = 1.536 Mbps
    • PCM (Pulse Code Modulation)
      • 8-bits x 8000 Hz
  • Codec (Coder / Decoder)
    • G.711 (Audio)
      • 56 or 64kbps
      • a-law / u-law
      • 8 bits compressed PCM
    • G.726 (Audio)
      • 16 to 40 kbps
      • Typically 32kbps
      • 100% savings in bandwidth over G.711
    • G.729 (Audio)
      • May Require Licensing
      • 6.4 to 11.8 kbps
      • Typically 8kbps
      • MAJOR savings in bandwidth
      • Mostly used in VoIP
      • Compressed in 10ms chunks
      • Does not work well with Fax or DTMF
        • These can be send using G.711 or another form of “Out-of-band” communication
  • Modulation
    • AM (Amplitude Modulation)
      • 2400 baud max
      • 2 different samples
    • FM (Frequency Modulation)
      • 2400 baud max
      • 2 different samples
    • PM (Phase Modulation)
      • 4800 baud max
      • 4 different samples
    • QAM (Quadrature with Amplitude Modulation)
      • 38400 baud max
      • 4 phase x 4 bits x 2400 baud = 38,400 baud
  • Asterisk
    • http:// www.asterisk.org
    • http:// www.digium.com
    • Open Source
    • Works on Linux, BSD, and OS-X
    • Channels
      • Bluetooth
      • FAX
      • H.323
      • IAX
      • ISDN
      • SIP
      • Skinny (SCCP)
      • Zap (FXS/FXO)
      • Pretty much anything else that does anything else
  • 3com NBX
    • Hopefully I can demo the Phone
    • NBX, Layer 2
    • Can ride in IP
  • Other Definitions
    • AA – Automated Attendant
    • ACD – Automatic Call Distributor
    • CTI – Computer Telephony Integration
    • Dial Plan - “Routing” table for phone systems
    • DTMF - Dual-Tone Multi-Frequency
    • Extension – End station / Node
    • FXO - Foreign Exchange Office
      • Receiver
      • Modem
    • FXS - Foreign Exchange Station
      • Provides battery (power)
      • Send Dialtone
    • IVR – Interactive Voice Response
    • Latency – end to end delay
    • Lineman Handset – Analog Telephone Line testing device
      • a.k.a. Butt Set or Test Set
      • Basically a telephone with alligator clips instead of a plug
    • Loop – single telephone line
  • Other Definitions
    • PBX - Private Branch Exchange
    • SIM - Subscriber Identification Module
    • Trunk – Multiple Lines acting as one
    • TTS – Text to Speech
    • VM – Voicemail
    • FWD – Free World Dialup
      • Free VoIP service
      • Does not provide free PSTN
    • LEC – Local Exchange Carrier
      • ILEC – Incumbent
        • Existed before AT&T breakup (1982)
        • Baby bells
      • CLEC – Competitive
        • After AT&T breakup
        • Most noted are Cable TV companies that provide phone over cable (Most of these are NOT VoIP providers)
  • References / Helpful Web links
    • http://www.wikipedia.org
    • http://www.freeworlddialup.com
    • http://asteriskathome.sourceforge.net/
    • http://www.nadcomm.com/timeline.htm
    • http://www.att.com/history/