The NTS-4000 is a IEEE1588 grandmaster clock, NTP stratum1 timeserver, and PRTC-A clock class network appliance. The std. version supports HQ OCXO holdover. The devices supports max. 4x LAN. The LAN1-2 support 100Mbps software time-stamping, upgradable to 10GbE*. Optional EXPANDER* NIC is available, supporting another 2x 1GbE with hardware time-stamping and PTP profiles. The NIC has own private PTP stack stored inside private FPGA. This approach ensures best cyber-security and high stability of synchronisation. Server supports 2x redundant GNSS receivers and redundant 2x power supplies. The sync I/O are: PPS, 10MHz, IRIG-B, ToD. This device is suitable for critical infrastructure support.