Hello Thabet,

A few details to collect;

1.) What version firmware are you using? Ensure the device is fully up to date

2.) After firmware upgrade/firmware flash, factory default the unit holding reset for 30 seconds

3.) Is the AP powered via POE? Ensure the power source has sufficient power source otherwise the AP will be crazy

4.) While the device is in a factory default state, can you connect to the default SSID, ciscosb?

5.) What is the distance from your wireless computer and the AP?

6.) What is the environment the device is installed? Is there glass for reflection, walls for absorption, cordless phones / moving metal objects for interference?

7.) When you do connect to the AP, if you check your wireless network card status, does the connection speed fluctuate? Example; You connect at 54 mbps, does the speed go up and down?

8.) Can you download the software INSIDDER and view the RSSI and overlapping networks?

9.) Can you manually set the port negotiation to 100 FULL on the device connecting to the AP

After these steps, if the devices continue to have issues, call the SBSC and have prepared your CCOID, Serial number of all 5 AP and provide this community link.

Here is the link for the SBSC numbers.

http://www.cisco.com/en/US/support/tsd_cisco_small_business_support_center_contacts.html