BNC (from Bayonet Neill–Concelman, sometimes erroneously named Bayonet Naval Connector) is the most common coaxial connector standard for measurement equipment up to 1 GHz.
It was patented in 1951 by Hazeltine Research, Inc. It is available in different impedances. 50 Ω is the most common.
Tektronix gear transitioned from UHF connectors to BNC connectors in the early to mid-1960's. For some pieces of equipment, a conversion kit was available.