Patent ID: 7991419

Claim:
A press-talk server in a communication system which achieves a half-duplex many-to-many call among a plurality of radio stations, the press-talk server which delivers voice information sent by a sending station as a radio station, which requests a talk burst, to a plurality of other radio stations through a gateway and a base station while passing or without passing through a transcoder, wherein if a packet is received, the press-talk server searches a press-talk table that stores call group identification information as an identifier of a press-talk call, received packet information indicating socket information of a packet to be receivable by a call of a call group, a coding system, and transmission packet information indicating socket information of a packet carrying voice information of a radio station, which is currently taking the talk burst, and checks whether an entry identical to the socket information of the received packet exists in the received packet information, if an entry exists, the press-talk server determines whether a source address of the received packet is an address of the gateway or an address of the transcoder, when the received packet is a packet from the gateway, for the call group identification information, the press-talk server refers to a talk burst table that stores socket information of a packet, and a talk burst request identifier for identifying a radio station, which is currently taking the talk burst, when the socket information of the received packet and the talk burst request identifier in the received packet are identical to the entries of the talk burst table, the press-talk server determines that the received packet is a packet which is to be delivered to other group members, the press-talk server refers to the press-talk table, according to transmission packet information corresponding to the received packet information of the received packet, copies the received packet if the transmission packet information has a plurality of socket information, and creates a transmission packet to the gateway and/or transcoder, when the created transmission packet is to be transmitted to the transcoder, the press-talk server refers to a sequence number table that stores a sequence number to be added to a packet when being transmitted to the transcoder in association with the call group identification information, inserts the sequence number into the transmission packet, and increments the sequence number of the sequence number table, and the press-talk server sends the completed transmission packet.