Called equipment selection method in ISDN packet switching mode and packet switching system for digital network

A called equipment selection method in a packet switching mode in a ISDN network including calling equipment and called equipment connected to said ISDN network for communication by packet switching, and further including a destination end system as an objective equipment to be connected to said called equipment for communication, comprising the steps of:

• upon occurrence of a call demand by said calling equipment, setting a sub-address of said called equipment and a network address of said destination end system in an address value field of an incoming call address extending facility of a call demand packet and transmitting said call demand packet to said ISDN network;
• in response to said call demand packet, transmitting a call setup message from said ISDN network to said called equipment;
• upon reception of said call setup message by said called equipment from said ISDN network, extracting said sub-address from an address value field of a destination sub-address information factor of said call setup message and making a judgement as to whether the incoming call is designated to own equipment by checking for a matching of the extracted sub-address and a given sub-address assigned to own equipment, and transmitting a response message to said ISDN network when the incoming call is judged to be designated to own equipment;
• in response to said response message, establishing a call and transmitting an incoming call packet from said ISDN network to said called equipment;
• and
• upon reception of said incoming call packet by said called equipment from said ISDN network, extracting the network address from said incoming call packet and performing incoming call processing based on the extracted network address.

A packet switching system in a digital network including a calling equipment and called equipment connected to said digital network for communication by packet switching, and further including a destination end system as an objective equipment to be connected to said called equipment for communication, comprising:

• an address setting means in said calling equipment for setting a sub-address of said called equipment and a network address of said destination end system in a call demand packet and transmitting said call demand packet to said digital network upon occurrence of a call demand in said calling equipment;
• means in said digital network for sending a call setup message to said called equipment in response to the call demand packet;
• an address extracting and matching check means in said called equipment for extracting said sub-address from said call setup message and making a judgement as to whether the incoming call is designated to own equipment by checking for a matching of the extracted sub-address and a given sub-address assigned to own equipment, and transmitting a response message to said digital network when the incoming call is judged to be designated to own equipment, upon reception of the call setup message by said called equipment from said digital network;
• means in said digital network for establishing a call and transmitting an incoming call packet to said called equipment in response to said response message;
• and
• call receiving means in said called equipment for extracting the network address from said incoming call packet and performing incoming call processing based on the extracted network address, upon reception of the incoming call packet by said called equipment from said digital network.