The TE 3-1939755-6 is a 220-position receptacle from the Free Height (FH) series, designed as a board-to-board mezzanine interconnect. The SMT termination and features like board guide, ground plate, and solder retention make it suited for high-density parallel board stacking in telecom, networking, or server equipment where signal routing density and a controlled impedance environment matter.
The 220 positions fill a long footprint; the ground plate on the connector body helps manage crosstalk between the outer and inner signal rows in a multi-pair mezzanine link. If your enclosure has a tighter gap, look at the lower-profile members of the FH series; if you need more clearance for component keep-outs on the underside of the top board, this height gives some headroom.