Network system and communication device

A network system, comprising:

• a first communication device;
• a second communication device composed separately from the first communication device;
• and
• a server composed separate from the first communication device, wherein the first communication device comprises:
• a first access device capable of accessing a network address, and
• an address sending device that sends a combination of the network address accessed by the first access device and communication device identification information of the first communication device to the server;
• wherein the server comprises:
• an address database that stores the combination of the network address and the communication device identification information sent from the address sending device,
• an identification information database that stores a combination of the communication device identification information and telephone identification information of a source, and
• an identification information identifying device;
• wherein the second communication device comprises:
• a telephone device that receives the telephone identification information,
• an address acquisition device that acquires the network address from the address database when the telephone device receives an incoming call, and
• a second access device capable of accessing the network address acquired by the address acquisition device;
• wherein the identification information identifying device identifies, from the identification information database, the communication device identification information combined with the telephone identification information received by the telephone device;
• and
• wherein the address acquisition device acquires, from the address database, the network address combined with the communication device identification information identified by the identification information identifying device.