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IEX8175 RF Electronics

Explore the transformation of long-distance calling from the black phone era to the digital PBX systems of today. Learn about the development of Open Telephony and Open Service Applications, and the evolution of Voice over IP (VoIP) technologies from 1996 to present day.

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IEX8175 RF Electronics

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  1. IEX8175 RF Electronics Avo Otstelekommunikatsiooni õppetool, TTÜ raadio- ja sidetehnika inst.avo.ots@ttu.ee

  2. Evolution “how can I make it stop ringing?” long-distance calling, ca. 1930 “does it do call transfer?” going beyond the black phone “amazing – the phone rings” catching up with the digital PBX 1996-2000 2000-2003 2004-

  3. Switching Network Open Telephony Open Service Application Layer (JAIN, AIN, TAPI,JTAPI, XML etc.) TDM/Circuit Switch Open/Standard Interface Line Concentration Call Control Connection Control Features Open Call Control Layer (SIP, H.323, MGCP, etc.) Digital Trunk Subsystem Common Channel Signaling Complex Administration Maintenance Billing Open/Standard Interface Standards-Based Packet Infrastructure Layer (IP, ATM) Brian Gracely, Cisco, 2001

  4. Channel Sharing Static Channelization Channel Sharing Techniques Scheduling Dynamic Medium Access Control Random Access

  5. VoIP Codecs

  6. Voice Packet • Codec G.729A (ITU – T))20 ms, =>Payload 20 octets Ethernet+FCS+Preamble: 26 bytes802.1q VLAN Tagging 4 bytesIP: 20 bytesUDP: 8bytes RTP: 12 bytes Voice Payload: 20 bytes----------90 bytes

  7. Overhead/payload

  8. Q o S

  9. Links http://www.ietf.org/rfc/rfc0791.txt?number=791 http://www.ietf.org/rfc/rfc0793.txt?number=793 http://www.packetizer.com/ http://en.wikipedia.org/wiki/VoIP

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