Hirose MS-156 is a subminiature coaxial switch, 1.6 mm High It seems to be the connector used for:
- 3com 3crshpw796
- 3Com 3CRWE154A72
- Conceptronic C54C
- Corega WLCB-54GT
- D-Link DWL-G650
- D-Link G664T (on the Mini-PCI daugherboard)
- Microsoft MN-520 has a connector like this underneath an adhesive strip
- Netgear MA401SE rev. D, Netgear WG511
Philips CPWNA100 (same as MN-520, see picture)
- SMC2632-ver2, SMC2635W
- SMC2835W (the Prism Nitro version, with "EZ Connect" in white over a red zone and a big "g" in blue) under the link and act leds adhesive strip
- Wistron USB clients like DCUA-81, DRUZ-81, etc.
- Cisco AIR-CB21AG-A-K9
- Asus WL-330G
- Nikon COOLPIX P1
- Linksys WUSB600N V2
Specs: http://www.hirose.co.jp/cataloge_hp/e35801678.pdf (Warning: Catalog says this connector is designed as a switch for testing purposes. So called Lock-Plugs are available and allow this to be used as permanent connector for external antenna. )
Example from 3com card: 
Read some posts about this connector: http://ajo.thinknerd.com/phpBB2/viewtopic.php?t=4 (Link is 404)
Additional Information
The datasheet shows "Lock type" connectors, so i don't think constant pressure is required. However, the mating connector is very bulky. also, these are DEFINITLY test points, and are therefore designed for only 100 mating/unmating connection cycles, so long term durability would be an issue. It is likely very lossy as well.
This is not the same as the friendly U.FL connector.
Added by MPI
This connector is not that lossy, it says that it's about 0.1 dB (which is about 3%). With corrosponding plug it is already 0.5 dB (About 11 % ) I have a WG511T (108Mbit) which seems to have this connector as well. The bad thing is that the connectors seem to be pretty high so they can't be fit underneath the housing of my Wireless card (Doh!)
Added by capouch
Does anyone know where to get one of said bulky connectors? I don't intend to have many insert/remove cycles, and would prefer not to solder!
Some people on the internets report success using a UFL plug glued to this connector. Will be able to confirm this soon (ewaldvangeffen@student.artesis.be)
