Communication system for starting teleconference between two multimedia stations over network

A communication system for carrying out a video conference between two video conference stations over a network, said system comprising:

• a source video conference station;
• a destination video conference station;
• first means, provided within said source video conference station, for generating a first random number in response to a connection start request, for transmitting said first random number to the destination video conference station, and for receiving a second random number from the destination video conference station;
• second means, provided within said destination video conference station, for generating a second random number in response to a connection start request, for transmitting said second random number to the source video conference station, and for receiving the first random number from the source video conference station;
• first control means for establishing a first connection between said two stations over a network by running a control and information connection protocol, in order for transmitting data in a full-duplex mode;
• second control means for establishing a second connection between said two stations over the network by performing a telewriting connection protocol in response to a connection request issued from one of said two video conference stations after said first connection is established, in order for transmitting data in a half-duplex mode;
• and
• determination means for allowing said one of said two stations to issue a telewriting connection request to the other station, based on the result of comparison between said first random number and said second random number, and for inhibiting the other station from issuing a telewriting connection request, based on said result of said comparison.

A communication system for carrying out a teleconference between two telewriting terminals over a network, said system comprising:

• a first telewriting terminal connected to a source teleconference station;
• a second telewriting terminal connected to a destination teleconference station;
• first data link protocol running means, provided within said first telewriting terminal, for generating a first random number in response to a connection start request, for transmitting said first random number to the second telewriting terminal, and for receiving a second random number from the second telewriting terminal;
• second data link protocol running means, provided within said second telewriting terminal, for generating a second random number in response to a connection start request, for transmitting said second random number to the first telewriting terminal, and for receiving the first random number from the first telewriting terminal;
• control means for establishing a telewriting connection between said two terminals over a network by performing a telewriting connection protocol in response to a telewriting connection request issued from one of said two terminals to the other terminal;
• and
• determination means for allowing said one of said two terminals to issue a telewriting connection request to the other terminal, based on the result of comparison between said first random number and said second random number, and for inhibiting the other terminal from issuing a telewriting connection request, based on said result of said comparison.