A data communications apparatus for communicating with another apparatus is disclosed. The data communications apparatus includes: a physical amount detection unit configured to detect changes of a first physical amount caused by contact with the another apparatus; a physical amount receiving unit configured to receive a signal including change information of a second physical amount of the another apparatus detected in the another apparatus when the first physical amount detected by the physical amount detection unit exceeds a predetermined value; a physical amount comparing unit configured to compare the changes of the first physical amount with the changes of the second physical amount to determine presence or absence of similarity; and a communication establishment unit configured to establish a communication with the another apparatus when the physical amount comparing unit determines that there is a similarity between the changes of the first physical amount and the changes of the second physical amount.