DATE: 14-12-2010

VOICE COMMUNICATION SYSTEM

Introduction

Voice communication system is a switching system which connects the various Air traffic controller positions to various Radio communication systems & Ground to Ground communication systems. Voice switching and routing between the communication systems and Air traffic controller working positions is done using advanced microprocessor and DSP.

Components of voice communication system

I. Central switching system.II. Controller working positions. (CWP)

III. Interfaces (Radio, Telephone, Network & Recording interfaces).IV. Monitoring and Control (Management system).

Central Switching System

Central switching system is the core of the VCS which switches the calls and control signals between CWPs and radio/telephone interfaces. Switching of signals between the CWPs and from interfaces to CWPs and vice versa is controlled by the central processor based on the stored configuration and user’s selection in the CWPs. The configuration is stored in the Flash memory and automatically loaded during each process. It provides central timing signals for inter wide system synchronization. It continuously monitors the health of critical systems and sends the information to Monitoring and control system.

Controller work positions

CWP is the User Interface which is provided to ATC personnel. CWP is provided with 230VAC supply. It has a power supply module which converts the AC into DC voltage and provides to the following subunits.

I. Human Machine Interface. The human machine Interface of VCS provides the users with voice and control access to the voice communication systems and associated communication resources connected to it.(Radio channels, Telephone channels & other CWPs). It has got touch entry screen which provides Graphic user interface consisting function keys, access buttons for radio/telephone/ other CWPs, dial pad & telephone book.

II. Position processor (EPOS). It converts the analogue voice and PTT signals into digital signals and sends them to CSS. In the same way, it converts digital data into voice signal and provides to speaker. It provides visual indication in the screen about the activity of channels and indication for incoming calls.

III. Interfaces Interfaces connect the external communication resources to VCS. Interfaces provides means to connect the following resources physically to the VCS

(1) Telephone connections(2) Radio communication systems (VHF Tx,Rx; HF Tx,Rx)(3) Digital and Analog recording outputs.(4) Networking Interfaces

Interfaces Exchanges the voice and signaling information between VCS and telephone/radio sources. In Frequentis VCS, Interfaces provides the connection between external communication sorces to VCS.

Monitoring & Control

It provides management of system configuration parameters and system software. It is used for the diagnosis of the fault. It provides the reports and logging of events.

Rack arrangement in Frequentis VCS

Description of modules in Frequentis VCS.

BCB Card provides the Interface for all the telephone connections. ERIF card acts as the Interface between VCS and Radio Communication Equipments GPIF card is the intermediate Interface card which can cater for eight Cards maximum

(Clock, SALI, SRO, ERIF and BCB) JIF card is the last level Interface which can be connected to CWPs & GPIF card provided

maximum number is four in any combination. HDLC card is connected with 13 JIF cards and connected to Data server. PSU module provides Redundant power supply to all the cards. PSU, Clock Module and Thermal management system don’t have micro processor. They are

Directly connected to SALI Card (Serial line alarm Interface)

External Connections to Frequentis VCS