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01 tdm voice introduction
1.
www.huawei.com Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. TDM Voice Introduction
2.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 1 Foreword Traditional voice network uses TDM technology and narrow band signaling to realize the voice transmission. This chapter describes the traditional voice network and basic voice transmission knowledge.
3.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 2 Objectives Upon completion of this course, you will be able to: Understand the traditional voice network; Understand the components, interfaces and signaling in the traditional voice network.
4.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 3 Phone Terminals Digital phone (Digital line) Advantages: more feature, easy to use, connect quickly Disadvantages: non-standard, expensive. Analog phone (Analog line) Advantages : universal, cheap Disadvantages: few feature, connect slowly Fax machine (Analog line) PSTN Phone: Digital Phone Analog Phone Fax PBX Fax Terminal
5.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 4 PBX PBX: Private Branch Exchange Trunk Card Signaling Processor Trunk Card Subscriber Card Control System Subscriber Card Switched Network
6.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 5 PBX Switching Matrix Common Control Analog Line Card Digital Line Card Data Line Card ISDN BRI Line Card Analog Trunk Card Digital Trunk Card User Interface Analog Trunks Digital Trunks Analog phone Digital phone Digital terminal ISDN terminal PSTN or PBX PSTN or PBX
7.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 6 Analog Line Electric currents are used to send analog signals. Each analog circuit is composed of a pair of wires. Time voltage Analog Phone Central Office Ground Battery (ring)-48V
8.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 7 Digital Line Digital signals use discrete values to represent levels of voice instead of a combination of electrical signals. 0 1 0 Central office Digital connection 1 1 1 0 1 Time slot #1 Time slot #0 Time slot #0 Time slot #1 Time slot #31 … … PBX …
9.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 8 Type of Circuit PSTN PBX Circuit Type Analog Circuit Digital Circuit Digital Circuit A digital circuit support multiple sessions at the same time Advantage: Digital signaling connect quickly, high port density, more calling information Disadvantage: The rent is more expensive Analog Circuit An analog circuit support only one session at the same time Advantage: Apply for the number of circuit as your need, the rent is more cheap Disadvantage: Analog signaling connect slowly, low port density, less calling information
10.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 9 Analog Circuit Analog Circuit FXS (Foreign eXchange Station): It is analog voice interface, also called subscriber interface, and it is the port that you plug a telephone, fax, or modem to provide telephony service. FXO (Foreign eXchange Office): It is the port on the device that connect to the CO or PBX, the port maybe on a telephone, fax and router that connects to the FXS port. Interface Call out Call in Opposite interface FXS Loop current variety Receive ringing current FXO FXO Close loop circuit Receive ringing current FXS PSTN PBXTelephone FXO FXS FXO FXS
11.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 10 Digital Circuit/Trunk PBX E1 Type Bandwidth Area Number Signaling Channel T1 1.544 Mbit/s North America, Japan, Hong Kong, Taiwan 24 23rd E1 2.048 Mbit/s Europe, Asia 32 16th E1 PSTN T1 T1 64kbps/channel
12.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 11 Signaling Signaling is the exchange information between involved points in the network that sets up, controls, and terminates each telephone call. Types of signaling Line Signaling: Loop start signaling, Ground start signaling. Inter-office signaling: CAS, CCS. Inter-office signaling Line Signaling PBX Phone PBX Phone
13.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 12 Loop Start Signaling Loop start signaling is a typical signaling between a user and the exchange. Voice signaling can be classified into three general types: Supervisory Addressing (Dual-Tone Multi-Frequency (DTMF) and Pulse) Informational-indicates call progress Analog phone Central office Ground -48V
14.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 13 Signaling - CAS CAS (Channel Associated Signaling): Signaling and audio are encoded and transmitted in the same channel. PSTN T1/E1 T1/E1 Signaling and Audio PBX
15.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 14 CAS - R2 R2 Signaling Line Signaling Inter-register Signaling PSTN E1 E1 Line Signaling Audio+ Inter-register Signaling PBX
16.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 15 Signaling - CCS CCS (Common Channel Signaling) transmits the signaling information (control information) on a separate channel from the audio. Signaling channel controls multiple audio channels. For example, PRA and SS7. PSTN T1/E1 T1/E1 SignalingAudio PBX
17.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 16 CCS - SS7 Signaling System No. 7 (SS7) is a set of telephony signaling protocols which are used to set up most of the PSTN calls. The network can be made up of several link types and three signaling nodes - Service Switching Point (SSPs), Signal Transfer Point (STPs), and Service Control Point (SCPs).
18.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 17 CCS - PRA PRA consists of B-channel and D-channel; T1 PRA consists of “23B+D”, E1 PRA contain ”30B+D”. PSTN E1/T1 E1/T1 D-channel: 64kbps 23 or 30 B-channel: 64kbps PBX
19.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 18 CCS - PRA Q.931 I.431/I.430 Q.921(LAPD) Point to point user signaling PRA 1 2 3 4 5 6 7 OSI Physical Layer Provides an electrical, mechanical, and procedural interface to the transmission medium. Data Link Layer Provides the functional and procedural means to transfer data between network entities and might provide the means to detect and possibly correct errors that may occur in the physical layer. Network Layer Responsible for packet forwarding including routing through intermediate routers, whereas the data link layer is responsible for media access control, flow control and error checking.
20.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 19 PRA Basic Call Flow SETUP networkcaller SETUP ACKNOWLEDGE ALERTING CONNECT CALL PROCEEDING CONNECT ACKNOWLEDGE
21.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 20 Traditional Voice Application Network … PBX Phone Phone New YorkBeijing … PBX Phone Phone PSTN SS7/PRA 1 2 Phone 3
22.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 21 Fax Application Fax machine can transmit signal through the existing PSTN telephone network. Fax machine needs modulation and demodulation for fax communication.
23.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 22 Modem A modem (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data.
24.
Copyright © 2014
Huawei Technologies Co., Ltd. All rights reserved. Page 23 Summary Traditional terminals and PBX structure. The narrow bandwidth trunk protocols about traditional voice network.
25.
Thank you www.huawei.com
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