The 3M ultra hard metric (UHM) socket connector is a fully-shielded 2 mm hard metric 2 mm hard metric connector designed for more than 7 Gbps backplane performance with a high signal density when used with unshielded industry standard 2 mm HM backplane headers. The UHM socket is designed to be intermateable to 2 mm HM IEC 61076-4-101 headers and is fully compatible with 2 mm HM PCB footprints.

The UHM socket connector’s unique design enables backplane designs using widely available standard 2 mm HM connectors to support greater than 7 Gbps performance, high signal integrity applications. Examples of backplane designs using 2 mm HM connectors are PICMG CompactPCI^® 3U and 6U and VITA VME 64x. Using the UHM socket connector, standard CompactPCI and VME 64x systems can support high density of multi-gigabit high speed serial IO protocols such as SAS, SATA, Rapid IO, PCI Express, and Gigabit Ethernet.

The UHM socket connector uses unique patented "virtual coaxial box" shielding technology to provide a tightly controlled impedance fully-shielded differential pair (100 ohm) or single ended (50 ohm), low crosstalk transmission path through the connector. Full shielding forms a virtual coaxial box around signal contacts individually and/or in pairs. This dramatically reduces crosstalk as compared to a standard unshielded 2 mm HM socket.

The UHM socket connector is available in 5-row (A, B, CL, CR, AB) and 8-row (D, E, DE, FL, FR) form factors allowing a very high signal density - 101 signals per linear inch for the 8-row and 63 signals per linear inch for the 5-row. The unique construction of the UHM socket connector supports 100 ohm differential pairs in rows or columns. Running differential pairs in rows eliminates row-to-row skew.