Руководство По Установке для Cisco Cisco Aironet 1200 Access Point

The 5-GHz radio module connects to the access point’s modified card bus 
connector and is available in three versions:

Low power IEEE 802.11a radio module with integrated antenna (RM20A 
radio module)

Enhanced IEEE 802.11a radio module with dual integrated antennas 
(RM21A radio module)

– Requires Cisco IOS Release 12.3(2)JA or later

Enhanced IEEE 802.11a radio module with dual external RP-TNC 
antenna connectors (RM22A radio module)

– Requires Cisco IOS Release 12.3 (2)JA or later

If you are upgrading to an 802.11g radio or an RM21A or RM22A 
radio module, make sure you are running the correct Cisco IOS 
version before you install the radio or module. If your access point 
is running an earlier version, it will not recognize the radio or 
module and continually boot.

All 5-GHz radios incorporate an Unlicensed National Information Structure 
(UNII) radio transceiver operating in the UNII 5-GHz frequency bands. The 
RM20A and RM21A contain dual integrated omnidirectional antennas for