Telecommunications Telephony Analog Access to the Telephone Network Courseware Sample 32964-F0 Order no.: 32964-00 First Edition Revision level: 01/2015 By the staff of Festo Didactic © Festo Didactic Ltée/Ltd, Quebec, Canada 2001 Internet: www.festo-didactic.com e-mail: [email protected] Printed in Canada All rights reserved ISBN 978-2-89289-541-4 (Printed version) Legal Deposit – Bibliothèque et Archives nationales du Québec, 2001 Legal Deposit – Library and Archives Canada, 2001 The purchaser shall receive a single right of use which is non-exclusive, non-time-limited and limited geographically to use at the purchaser's site/location as follows. The purchaser shall be entitled to use the work to train his/her staff at the purchaser's site/location and shall also be entitled to use parts of the copyright material as the basis for the production of his/her own training documentation for the training of his/her staff at the purchaser's site/location with acknowledgement of source and to make copies for this purpose. In the case of schools/technical colleges, training centers, and universities, the right of use shall also include use by school and college students and trainees at the purchaser's site/location for teaching purposes. The right of use shall in all cases exclude the right to publish the copyright material or to make this available for use on intranet, Internet and LMS platforms and databases such as Moodle, which allow access by a wide variety of users, including those outside of the purchaser's site/location. Entitlement to other rights relating to reproductions, copies, adaptations, translations, microfilming and transfer to and storage and processing in electronic systems, no matter whether in whole or in part, shall require the prior consent of Festo Didactic GmbH & Co. KG. Information in this document is subject to change without notice and does not represent a commitment on the part of Festo Didactic. The Festo materials described in this document are furnished under a license agreement or a nondisclosure agreement. Festo Didactic recognizes product names as trademarks or registered trademarks of their respective holders. All other trademarks are the property of their respective owners. Other trademarks and trade names may be used in this document to refer to either the entity claiming the marks and names or their products. Festo Didactic disclaims any proprietary interest in trademarks and trade names other than its own. Safety and Common Symbols The following safety and common symbols may be used in this manual and on the equipment: Symbol Description DANGER indicates a hazard with a high level of risk which, if not avoided, will result in death or serious injury. WARNING indicates a hazard with a medium level of risk which, if not avoided, could result in death or serious injury. CAUTION indicates a hazard with a low level of risk which, if not avoided, could result in miinor or moderate injury. CAUTION used without the Caution, risk of danger sign , indicates a hazard with a potentially hazaardous situation which, if not avoided, may result in property damage. Caution, risk of electric shhock Caution, hot surface Caution, risk of danger Caution, lifting hazard Caution, hand entanglement hazard Notice, non-ionizing radiation Direct current Alternating current Both direct and alternating current Three-phase alternating current Earth (ground) terminal Safety and Common Symbols Symbol Description Protective conductor terminal Frame or chassis terminal Equipotentiality On (supply) Off (supply) Equipment protected throughout by double insulation or reinforced insulation In position of a bi-stable push control Out position of a bi-stable push control We invite readers of this manual to send us their tips, feedback and suggestions for improving the book. Please send these to [email protected]. The authors and Festo Didactic look forward to your comments. Table of Contents Introduction ................................................. V Courseware Outline Analog Access to the Telephone Network ....................... VII Central Office Operation ...................................... IX Private Automatic Branch Exchange (PABX) ...................... XI PABX Analog Trunk ........................................ XIII Digital Trunk.............................................. XV Sample Exercise Extracted from Analog Access to the Telephone Network Ex. 2-2 Hybrid Function ......................................3 Sample Exercise Extracted from Central Office Operation Ex. 3-1 Call Processor Functions .............................17 Sample Exercise Extracted from Private Automatic Branch Exchange (PABX) Ex. 1-1 Architecture of a Digital PABX ..........................31 Sample Exercise Extracted from PABX Analog Trunk Ex. 1-2 Analog Trunk Interface ...............................55 Sample Exercise Extracted from Digital Trunk Ex. 1-2 Digital Trunk Interface ................................87 Other Sample Extracted from Analog Access to the Telephone Network Unit Test ................................................117 Instructor Guide Sample Extracted from Analog Access to the Telephone Network Unit 1 The Telephone Set .................................121 Bibliography III IV Introduction The Lab-Volt Telephony Training System (TTS), Model 8086, is a powerful learning tool that allows students to study the operation of modern telephone networks and digital private automatic branch exchanges (PABX). The TTS is built upon the Reconfigurable Training Module, Model 9431. This module, which uses state-of-the- art digital signal processor (DSP) technology, can be programmed to act as different parts of a telephone network. Interface cards that students install in the training module allow connection of real analog and digital telephone sets and trunk lines. A central office (CO) is easily implemented by inserting an analog line interface card into a training module programmed to act as a central office. Similarly, a digital PABX is implemented by inserting a digital telephone interface card into a training module programmed to act as a PABX. Furthermore, simple telephone networks can be set up quickly by adding analog and digital trunk interface cards to COs and PABXs implemented with training modules, and interconnecting the modules with trunk lines. Such telephone networks allow establishment of both intra- and inter- exchange calls as well as tandem-switched calls. A Pentium-type host computer, connected to the Reconfigurable Training Module through a high-speed data link (Ethernet link with TCP/IP protocol), runs the Lab-Volt Telephony Training System (LVTTS) software. This Windows®-based software is used to download programs into the DSP memory of the Reconfigurable Training Module. The LVTTS software is also used to: • display the functional block diagram of the telephony equipment (CO, digital PABX, etc.) implemented in the Reconfigurable Training Module, • change various system settings and options, such as the telephone ringing cadence, companding type, subscriber names and phone numbers, etc, • perform step-by-step observation of call routing sequences, • observe real signals throughout the system in both the time and frequency domains using modern virtual instruments, • insert faults in the system (password-protected feature) for troubleshooting purposes. The TTS courseware material consists of a series of five student manuals, an instructor guide for each student manual, and a user guide. The following fields of telephony are covered in the TTS courseware: • Analog Access to the Telephone Network • Central Office Operation • Private Automatic Branch Exchange (PABX) • PABX Analog Trunk • Digital Trunk Each student manual covers one particular subject and is divided into several units. Each unit consists of a series of hands-on exercises dealing with certain aspects of telephony. The exercises contain a clearly stated objective, a discussion, a summary of the exercise procedure, a detailed exercise procedure, a conclusion, and a set of review questions. A ten-question test at the end of each unit allows the instructor to verify the knowledge gained by the student. Each instructor guide provides the measured results as well as the answers to all questions of each exercise in the corresponding student manual. It also provides the answers to the unit test questions. The user guide provides all the information required to set up and use the Telephony Training System. V VI Courseware Outline ANALOG ACCESS TO THE TELEPHONE NETWORK Unit 1 The Telephone Set Introduction to the public switched telephone network (PSTN). Brief description of the central office. Familiarization with the functions and operation of the analog telephone set. Ex. 1-1 Telephone Ringing Telephone ringing. AC ringing voltage specifications. The electronic telephone ringer circuit. Ex. 1-2 The Telephone Switchhook and Handset Operation of the telephone switchhook. The handset and speech circuit. Functions and operation of the speech circuit. Ex. 1-3 Tone Dialing Familiarization with DTMF tone dialing. Frequencies used in DTMF dialing signals. Ex. 1-4 Pulse Dialing Familiarization with pulse dialing. Pulse timing. Pulse dialing with an electronic-type analog telephone set. Unit 2 The Line Interface Role of the analog line interface. Block diagram of the analog line interface. Functions of the analog line interface (BORSCHT functions). Operation of the analog line interface. Ex. 2-1 Battery Feed Power Supply How electrical power is supplied to analog