Digital Switching System

Digital Switching System

58-002

The Digital Switching System is an easy to use trainer for the investigation of digital telephone switching circuits and their applications. With this system a student may study the principles of digital switching in telephony and also gain experience into modern telephony practice. The modules use both current standard telephony devices as well as special circuits designed to develop an understanding of the methods employed.

The system allows the performance of a wide range of experiments within the subject area to be investigated. Assignments include general introductory material and each practical is supported by background information and tutorial questions, in the standard Feedback Discovery format.

The System comprises a digital switching centre, a controller, four telephones and Discovery software. It is complementary to the Feedback Telephony Training System, 58-001. Protection is provided on all units to ensure there are no dangerous voltages accessible by the students.

Controller
The Controller contains the microprocessor-based circuitry for control and the special power supplies required by the telephones and their associated circuits. It interfaces with the PC through a card supplied with the system, with controlling code downloaded from the PC on switch-on. This makes for uncomplicated upgrading via the Discovery software. Up to three exchanges may be run from one controller.

Digital Switching Centre
The Digital Switching Centre is an open-board format unit containing four complete telephone line circuits and all the digital switching and signalling associated with a modern digital telephone system. Two connections to other digital switching centres (trunk interfaces), four telephones and a convenient tray for housing them are also provided. A system containing two switching centres may be set-up using an additional, optional Digital Switching Centre board.

Computer Connection
The system is supplied with software and hardware to interface to a PC. Power Supply All power supplies required by the system are provided with the trainer.

• Features

  • Relevant to study of Central Switching exchanges or PAB exchanges
  • Uses commercial CODECs

• Subject Area

  • Local Signalling
  • Operation
  • Tones and Cadences
  • Digital Switch Principles
  • Time Switching
  • Time & Space Switching
  • Digital Switch Control
  • Control of Time Switch
  • Connection of Tones
  • Line Scan
  • Switch Hook
  • DTMF Receivers
  • Call Records
  • Call State
  • Line Identities
  • Call Time
  • Line Records
  • Directory Numbers
  • Call Accounting
  • Line Maps
  • Location Maps
  • Condition Maps
  • State Transition
  • Inputs
  • Outputs
  • Tasks
  • Call Progress
  • Call Set Up
  • Call Suspension
  • Call Release
  • Manual Control
  • Control
  • Testing
  • Test out and Loop Back
  • Traffic
  • System Traffic