A radio communication system comprising: a first radio terminal assigned a first absolute ID; and a second radio terminal assigned a second absolute ID, said first and second radio terminals (B, A) having capability of performing radio communication with each other using said first and second absolute IDs in conformity with a predetermined radio communication standard, wherein said first radio terminal has a memory device for storing a combination of said first absolute ID and a local ID for distinction of said first radio terminal within a local area network constituted by said first and second radio terminals (B, A), said second radio terminal has capability of transmitting a search signal for searching a target radio terminal, said first radio terminal is configured to transmit, upon receiving said search signal, a response signal containing said combination of said first absolute ID and said local ID, said second radio terminal is configured to validate, upon receiving said response signal from said first radio terminal, said local ID, and to transmit a communication establishment request signal for requesting communication with said first radio terminal as said target radio terminal if said local ID is determined to be valid, said first radio terminal is a portable scanner unit; said second radio terminal is a relay unit; said radio communication system further comprises a host computer; and said second terminal has capability of relaying data received from said first radio terminal to said host computer through cable communication, and capability of performing character code conversion on data transmitted between said host computer and said second radio terminal and on data transmitted between said first radio terminal and said second radio terminal. a first radio terminal assigned a first absolute ID; and a second radio terminal assigned a second absolute ID, said first and second radio terminals (B, A) having capability of performing radio communication with each other using said first and second absolute IDs in conformity with a predetermined radio communication standard, wherein said first radio terminal has a memory device for storing a combination of said first absolute ID and a local ID for distinction of said first radio terminal within a local area network constituted by said first and second radio terminals (B, A), said second radio terminal has capability of transmitting a search signal for searching a target radio terminal, said first radio terminal is configured to transmit, upon receiving said search signal, a response signal containing said combination of said first absolute ID and said local ID, said second radio terminal is configured to validate, upon receiving said response signal from said first radio terminal, said local ID, and to transmit a communication establishment request signal for requesting communication with said first radio terminal as said target radio terminal if said local ID is determined to be valid, said first radio terminal is a portable scanner unit; said second radio terminal is a relay unit; said radio communication system further comprises a host computer; and said second terminal has capability of relaying data received from said first radio terminal to said host computer through cable communication, and capability of performing character code conversion on data transmitted between said host computer and said second radio terminal and on data transmitted between said first radio terminal and said second radio terminal.