TNC connector

Left, a male RP-TNC connector from a 2.4GHz antenna. Right, a standard male TNC connector on a UHF antenna.

Reverse-polarity TNC (RP-TNC, sometimes RTNC) is a variation of the TNC specification which reverses the polarity of the interface. This is usually achieved by incorporating the female contacts normally found in jacks into the plug, and the male contacts normally found in plugs into the jack.[5]

Because they were not readily available, RP-TNC connectors have been widely used by Wi-Fi equipment manufacturers to comply with specific local regulations, such as those from the FCC,[6] which are designed to prevent consumers from connecting antennas which exhibit gain and therefore breach compliance. The FCC considered that the RP-TNC was acceptable in preventing consumers changing the antenna; but by 2000 it regarded them as readily available,[7] though delaying its ruling indefinitely.[8] As of 2013, leading manufacturers are still using RP-TNC connectors on their Wi-Fi equipment.[9] Plug on the female connector and receptacle on the male when dealing with RP-TNC.

The TNCA connector is a variant of the TNC connector specified in MIL-STD-348[1] designed to provide an air gap in the dielectric region between the male and female connectors. The socket version of the TNCA connector is nearly identically to the standard TNC connector, while the pin contact version provides the air cavity differentiating it from a standard TNC connector, as such TNCA connectors are mechanically compatible and matable with standard conjugate TNC connectors.

Most TNC connectors are 50-ohm type even when used with coaxial cable of other impedances, but a 75-ohm series is also available, providing a good SWR to about 1 GHz.[10] These can be recognized by a reduced amount of dielectric in the mating ends. They are intermatable with standard types.