Glenair https://www.glenair.com/catalogs/mil-dtl-38999-cylindrical-connectors.pdf
https://www.te.com/content/dam/te-com/documents/aerospace-defense-and-marine/aerospace/global/connectors/1-1773858-4_38999Overview.pdf TE Connectivity
https://www.glenair.com/catalogs/mil-dtl-38999-series-iii-and-iv.pdf
originated during World War 2, when United States military needs rugged connector for their aircrafts
It is trustes by various industries.
they last long in harsh environment.
they are meant to be good with (EMI) Electromagnetic Interference
MIL-DTL-38999 (commonly referred to simply as 38999, formerly MIL-C-38999) is a United States military standard specification for high-density, environmental-resistant, circular interconnects.
It is not merely a size standard. It is a comprehensive performance, mechanical, and interface specification that dictates:
- Coupling mechanisms (threaded, bayonet, or breech-lock).
- Shell geometries and dimensional envelopes (Shell sizes 9 through 25, designated A through J).
- Insert arrangements and contact systems (high-density arrangements accommodating power, signal, RF coaxial, twinax, quadrax, and fiber optics).
- Environmental survivability (vibration profiles, shock up to 300g, temperature extremes from to , hermetic sealing, and fluid resistance).
- EMI/RFI shielding effectiveness (360-degree shell-to-shell grounding spring fingers).
- Blind-mate and damage prevention (“scoop-proof” shell architectures).
MIL-DTL-39029 contacts