Hi Tian,
The AP Model AIR-LAP1242AG-C-K9 is a LWAPP (Lightweight) Access Point. These are meant to work with the Wireless Lan Controller not standalone. This can be fixed if you load an IOS on the 1242:) You could always send it back and get the AIR-AP1242AG-C-K9 (notice no "L") version.
Here is a conversion method;
Reverting the Access Point Back to Autonomous Mode
http://www.cisco.com/en/US/products/hw/wireless/ps430/prod_technical_reference09186a00804fc3dc.html#wp161272
You can convert an access point from lightweight mode back to autonomous mode by loading a Cisco IOS Release that supports autonomous mode (Cisco IOS release 12.3(7)JA or earlier). If the access point is associated to a controller, you can use the controller to load the Cisco IOS release. If the access point is not associated to a controller, you can load the Cisco IOS release using TFTP.
Using a TFTP Server to Return to a Previous Release
Follow these steps to revert from LWAPP mode to autonomous mode by loading a Cisco IOS release using a TFTP server:
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Step 1 The static IP address of the PC on which your TFTP server software runs should be between 10.0.0.2 and 10.0.0.30.
Step 2 Make sure that the PC contains the access point image file (such as c1200-k9w7-tar.122-15.JA.tar for a 1200 series access point) in the TFTP server folder and that the TFTP server is activated.
Step 3 Rename the access point image file in the TFTP server folder to c1200-k9w7-tar.default for a 1200 series access point, c1130-k9w7-tar.default for an 1130 series access point, and c1240-k9w7-tar.default for a 1240 series access point.
Step 4 Connect the PC to the access point using a Category 5 (CAT5) Ethernet cable.
Step 5 Disconnect power from the access point.
Step 6 Press and hold MODE while you reconnect power to the access point.
Step 7 Hold the MODE button until the status LED turns red (approximately 20 to 30 seconds) and then release.
Step 8 Wait until the access point reboots, as indicated by all LEDs turning green followed by the Status LED blinking green.
Step 9 After the access point reboots, reconfigure it using the GUI or the CLI.
From this doc;
http://www.cisco.com/en/US/products/hw/wireless/ps430/prod_technical_reference09186a00804fc3dc.html#wp161272
Hope this helps!
Rob
