This read-write value selects the transmit clocking mode for the DTE port: slaveNormal(1) clocks transmit data from the DTE using an internally generated clock, slaveInvert(2) inverts that internally generated clock before sampling the transmit data, and external(3) uses the DTE's own EXTCLK signal to clock transmit data instead. Admins set it to resolve clock-phase or timing-source mismatches with the connected DTE equipment. For example, an admin experiencing bit errors that clear up when switching to slaveInvert(2) has likely resolved a clock-phase alignment issue between the probe and the connected DTE.