一、Description of Demand

    Currently the voice communication of the electrical power system, taking the local department as the example, is divided into the telephone for administrative department and that for dispatching department, both of which adopt the self-established communication network to solve the voice communication for department buildings and transformer stations. The administrative telephone system is basically realized by adopting the Siemens digital SPC switch system to switch calls to each county power supply bureau or to the remote users, and the dispatching telephone system is mainly used between the transformer stations of all levels by adopting HARRIS or Siemens digital SPC switch system over SDH transmission network and PCM mode. In addition to solve the voice communication for the department buildings and transformer stations, the electric power system still adopts the network of the telecom operator to solve the voice communication for many power supply business stations. The business stations and transformer stations of the electric power system are in large amount and dispersed distribution, with high requirements in the reliability, management, maintenance and simpleness for the voice communication system. At present, each power supply bureau has established the 100M IP information network which has covered all power supply business stations. It becomes feasible to solve the voice communication of the power supply business stations by using the VoIP voice technology, enabling the resource of IP information network to be fully utilized.

二、Device Allocation

    The computer center of the electric power bureau is allocated with the IP softswitching DVS-1000 system. The repeater gateway DVG-1000 or DVS-1000 mutually communicating with PSTN system can be connected to the devices provided by the telecom operator.

    Each business station is allocated with the DVG-1000 series access gateway, of which the down link is connected to the general telephones at the offices, etc., and the up link is to the Ethernet interface for the access of IP data network of electric power system.