First electrical White Rabbit absolute calibration inter-comparison

A time transfer link consisting of PTP White Rabbit (PTP-WR) devices can transfer time with sub-nanosecond accuracy. Originally White Rabbit devices were calibrated as a set of two devices. Progress in calibration makes individual absolute calibrated PTP-WR devices possible. This enables exchange of PTP-WR devices without the need for expensive in-situ end-to-end calibrations. Electrical absolute calibration is the basis of absolute calibration. It calibrates the time relationship between the internal timestamp and the external electrical time reference plane. In this paper we examine the electrical time transfer accuracy when a link is setup using electrical absolute calibrated PTP-WR devices calibrated by different laboratories.