Before revision: In data communication, an errored second is an interval of a second during which any data error whatsoever has occurred, regardless of whether that error was a single bit error, or a complete loss of communication is not important.
After revision: In bit communication, an errored second is an interval of a second during which any data error whatsoever has occurred, regardless of whether that error was a single bit error, or a complete loss of communication is not important.