The card is based on a powerful CPU with dedicated 10/100 Mbits/s Ethernet LAN controller and a large FPGA device for direct NTP packet time stamping, which is done at the physical interface level. NTP system clock is derived from the US5G-US5Ge local clocks (Rubidium or OCXO quartz). UTC time and PPS synchronization are routed to IOP1, IOP2 through backplane. Two LAN interfaces (10/100baseT) are available on the front of the card for the US5Ge or at the rear face for the US5G.

Craft port is also available for local NTP supervisory. TOD interface with accurate PPS reference can be directly connected to UNISYNC TOD port. Front LED’s are used to monitor NTP card activity.  NTP card(s) provisioning and monitoring are under control of the US5G-US5Ge COM management card and thus separated from the NTP dedicated LAN Ethernet interfaces.

Currently, BITS (Building Integrated Timing Supply) equipments are used to deliver high availability precision frequency references to network elements. Now, GPS receivers are often associated to BITS as complementary frequency references. Hearts of the BITS, synchronization units like US5G or US5Ge have to complete frequency reference features with accurate network timing capabilities. Network timing references are used for date and time distribution through IP Networks to Clients like PC’s, billing machines and others.

This HW assisted NTP card is directly connected to the US5G backplane. High quality local oscillators (Rubidium or low aging quartz) available into IOP redundant modules are used as the system clock of the NTP card, maintaining a very high stability and low jitter reference for the NTP server reference clock.

The card works as a server stratum level 1 when PPS and UTC time reference are available. The US5Ge unit is able to retrieve PPS reference signals (driven by the IOP GPS sources) through its backplane. The US5G unit is also able to handle PPS reference signals through its ToD interface and complementary UNISYNC PRS unit. In case of PPS unavailability, the NTP card works as a lower level stratum server connected to NTP network servers.