Electronic – What connector is similar to U.FL but has no pin

connectoridentificationRFwifi

I am trying to identify this connector style:

enter image description here

Look at the two RF micro-coax connectors on the left, just next to the PCB antennas. They look identical to U.FL or IPEX but have no central pin. What are these, and what are they used for?

This is what U.FL looks like for a comparison:

enter image description here

Best Answer

It's a special switched connector for testing or using external antennas. Notice that there is a trace on both sides of the connector, but only one side on the u.fl connector. When you plug a test connector into the jack, it actually disconnects the signal flowing through it and routes it out the test connector instead. They show up all the time in wireless routers and the like because they can be used to perform accurate tests on the radio with the antenna disconnected before it ships. They can also be used to add an external antenna to a device by bypassing the internal antenna. This is one series of this type of connector:

http://www.ttiinc.com/object/Murata-Switch-Connectors-HSC-RF-Coaxial.html