A tester for integrated circuits on a silicon wafer includes an input/output connection for testing an integrated circuit. The tester comprises circuitry arranged for transferring a first data frame to the integrated circuit via the input/output connection, the first data frame including a time reference for the data included in the data frame, a field for validating the time reference and a data field including at least one test command and for receiving a second data frame via the input/output connection, the data in the second data frame received having a duration that is a multiple of the time reference.