N Terminator Plug & Jack 50 Ohm
The N connector follows the MIL-C-39012 standard, defined by the US military, and comes in 50 and 75 ohm versions. The 50 ohm version is widely used in the infrastructure of land mobile, wireless data, paging and cellular systems. The 75 ohm version is primarily used in the infrastructure of cable television systems. Connecting these two different types of connectors to each other can lead to damage due to the difference in diameter of the center pin Unfortunately, many type N connectors are not labeled, and it can be difficult to prevent this situation in a mixed impedance environment. The situation is further complicated by some makers of 75 ohm sockets designing them with enough spring yield to accept the larger 50ohm pin without irreversible damage, while others clearly do not, and expect users to segregate their connectors and adaptors. In general a 50 ohm socket is not damaged by a 75 ohm pin, but the loose fit means the contact quality is not guaranteed.
The 50 ohm type N connector is favored by enthusiasts who create their own Wireless LAN antenna systems, which run at 2.4 GHz or 5 GHz. The Cantenna is one such design. The enthusiasts have settled on using the N connector as a standard connection for homebrew antennas. By using a cable with an N connector one can easily interchange homebrew antennas. 50Ω N connectors are also commonly used on amateur radio devices (e.g., transceivers) operating in UHF bands.