C-DOT EXCHANGE
C-DOT EXCHANGE
C-DOT MAX Family of exchanges employs T-S-T switching architecture and can be configured from four basic modules: -
- Base Module
- Central Module
- Administrative Module
- Input-Output Module
The base module (B.M.) is the basic growth unit of the system interfaces external world to the switch and provides local resources such as tones announcements and terminal test facility. Presently, the enhanced announcement card (EAC) equipped per BM is being used for providing limited intelligent peripheral (IP) functions to the SSP.
The interfaces may be subscriber lines, analog and digital trunks, CCB and PBX lines and digital links from remote modules. Each base module can interface up to 2024 terminations. The no. Of base modules directly corresponds to exchange size. It cares out majority of call processing connection and in a small exchange application, also carries operation and maintenance function with the help of input output modules.
In the single base module (SBM) exchange configuration, the base module acts an independent switching system and provides connection to up to 1500 lines and so trunks. In such a configuration, the base module directly interface with the input output module for bulk data storage and operations and maintenance function clock and synchronization is provides by a source with in the base module.
The central module (CM) consists of a message switch and a space switch for Inter module communication and we send data switching between base modules. It provides central message communication between any two base modules, and between base modules and the administrative module for operation and maintenances function. It also provides clock and synchronization on a centralize basis.
Administrative module (AM) performs system level rescuer allocation and processing function on a centralized basis. It performs all the memory and time interfaces call processing support function and also administration and maintenance function. It communication with the base modules via the central module. It supports the input output module for providing man – machine interface. It also supports an alarm display panel (ADP) for the audio – visual indication faults in the system. In SBM configuration, ADP directly communicates with the base processor.
CCS7 signal unit module (SUM) is based on duplicated 68020 or 68040 microprocessors and provides CCS7 signaling capability to the switch. However it resides one of the BMs just like terminal unit frame. The approach makes it an easily verifiable module.
The SUM provides up to 64 signaling terminals, which can be configured as internal message channels or external signaling links. The basic growth unit in the SUM in the signaling handler module (SHM) card which contains 8 signaling terminals. The no. Of these cards equipped will depend upon the internal and external connection requirements. Internally, the SUM communicates with the BM’s main processor for initializes and application processing. Externally, the Sum provides CC57 network connectivity to other switching nodes. STP’s and SCPs.
Input Output Module (IOM) is powerful duplex computer systems that interface various secondary devices like disk drives, cartridge tape drive and floppy drive. It supports printers and up to 16 video display units that are used for man machine communication interface. All the bulk data processing and storage is done in this module.
Thus, a C-DOT DSS MAX exchange, depending up on its size and application, will consist of Base modules (maximum 32), Central Module, Administrative module, Signaling Unit Module, Input Output Module, and Alarm Display panel. The Base Module can be remotely located or co-located depending up on the requirement.
C-DOT DSS MAX SOFTWARE ARCHITECTURE
The Main subsystems of C-DOT DSS MAX software are briefly described below. Their place in the overall software architecture is depicted
C-DOT Real Time Operating System (CDOS)
The operating system is primarily responsible for the following function and services
- Management of Processes
- Synchronization and Communication between processes
- Time Management
- Interrupt Handling
- Resource Management
- Memory Management
- On-Line And Off-Line Debugging Facility
Peripheral Processor Subsystem
The Software for handling line, trunk, and service circuit is resident as in the peripheral Processors. Presently, these are 8-bit microprocessors programmed in assembly language. The Main activity of the peripheral software is to detect events and communication them to the Base Processor, Where logical Call Handling is done. This subsystem also carries out the commands given by the base Processor for generating suitable telephony events on the outgoing lines and trunks.
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