serial communication The transmission of information between computers or between computers and peripheral devices one bit at a time over a single line (or a data path that is 1 bit wide). Serial communications can be either synchronous or asynchronous. The sender and receiver must use the same data transfer rate, parity, and flow control information. Most modems automatically synchronize to the highest data transfer rate that both modems can support. pcAnywhere uses the asynchronous communications standard for personal computer serial communications.