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IEX8175 RF Electronics. Avo Ots telekommunikatsiooni õppetool, TTÜ raadio- ja sidetehnika inst. avo.ots@ttu.ee. 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”.
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IEX8175 RF Electronics Avo Otstelekommunikatsiooni õppetool, TTÜ raadio- ja sidetehnika inst.avo.ots@ttu.ee
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-
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
Channel Sharing Static Channelization Channel Sharing Techniques Scheduling Dynamic Medium Access Control Random Access
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
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