When looking for SMA you may find SMA and RP-SMA connectors. What is the difference in these two?
Reverse polarity SMA (RP-SMA or RSMA) is designed to be incompatible with standard SMA connectors to comply with U.S. FCC regulations which seek to prevent consumers from attaching non-standard aerials to wireless devices.
The male RP-SMA connector has the same external housing as a standard male SMA connector except the center male pin is replaced by a receptacle. The female RP-SMA connector has the same housing as a standard female SMA connector however the pin found on a male SMA connector is on the female RP-SMA connector.
Here are some picture examples to help show the difference.
