Wireless Network with more then 70 AP (AIR-LAP1242G-E-K9 and AIR-LAP1142N-E-K9). About 200 WireLess clients (PC, Cisco-Phone, Vehicle-Mounted Computers, etc.) on several WLANs. All managed by 3 WLC (4404 - 18.104.22.168) and WCS (22.214.171.124). The IOS of the AP is 12.4(18a)JA2.
I have a problem with some OLD Vehicle-Mounted Computers. This are LXE VX1, only 802/1b (only 1Mb/s), no WPA, only MAC authentication. I am not able to associate this clients, even if disabling MAC-authentication (all open). Looking on the WCS, I don't see events related to this clients, no entry in LOGs, no entry in Monitor -> clients -> probing Clients. Some "incompatibility" on Radio?
But the clients are OK: with a stand-alone AP (AIR-AP1242AG-E-K9 - 12.4(10b)JDA) they can associate (different SSID, of course).
This could be for several reasons. I noticed that you have a mix of 1242 and 1142 APs. The 1142 APs they are N devices. I know some old clients will have a lot of issues conecting on mix environments" where there is B, G and N enabled, most likely B clients so it is a good test to disable N there.
Also, I will recommend to disable most of the options on the WLAN advance settings, to make the most compatible configuration for old clients (disable MFP, client exclusion, Aironet IE...).