The 50-39-5288 is CONN IC DIP SOCKET 28POS TINLEAD, that includes DIP, 0.6" (15.24mm) Row Spacing Type, they are designed to operate with a Through Hole Mounting Type, Features is shown on datasheet note for use in a Closed Frame, that offers Number of Positions or Pins Grid features such as 28 (2 x 14), Pitch Mating is designed to work in 0.100" (2.54mm), as well as the Tin-Lead Contact Finish Mating.

503948400 with user guide, that includes 24-30 AWG Wire Gauge, they are designed to operate with a Milli-Grid? 50394 Series, Pin or Socket is shown on datasheet note for use in a Socket, that offers Packaging features such as Bulk, Contact Termination is designed to work in Crimp, as well as the Flash Contact Finish Thickness, the device can also be used as Gold Contact Finish.

503957-2 with circuit diagram, that includes LightCrimp Series, they are designed to operate with a LC, SC, ST Connectors Specifications, Type is shown on datasheet note for use in a Termination Kit.

503948-5 with EDA / CAD Models manufactured by TE CONNECTIVITY/AMP. The 503948-5 is available in SC CONNECTORS Package, is part of the IC Chips.