IEX8175 RF Electronics

1
IEX8175 RF Electronics

• Avo Otstelekommunikatsiooni õppetool,
• TTÜ raadio- ja sidetehnika inst.avo.ots_at_ttu.ee

2
Evolution
how can I make it stop ringing?
does it do call transfer?
long-distance calling, ca. 1930
going beyond the black phone
amazing the phone rings
catching up with the digital PBX
1996-2000
2000-2003
2004-
3
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
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VoIP Codecs
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Voice Packet

• Codec G.729A (ITU T))20 ms, gt Payload 20
  octets
• EthernetFCSPreamble 26 bytes802.1q VLAN
  Tagging 4 bytesIP 20 bytesUDP
  8 bytes RTP 12
  bytes Voice Payload 20
  bytes ---------- 90 bytes

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Overhead/payload
8
Q o S
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Links

• http//www.ietf.org/rfc/rfc0791.txt?number791
• http//www.ietf.org/rfc/rfc0793.txt?number793
• http//www.packetizer.com/
• http//en.wikipedia.org/wiki/VoIP