What is the clear CAV data tab for in service mode

This is used in Service Mode to help determine the bidirectional RF strength and coverage levels between the MX40 and the Access Points and network. There's several pages of in-depth technical discussion starting on page 8-15 of the service manual (I'm looking at rev B.06.5X). If pushed, it'll force another RF assessment. Tricky, if you don't know what you're doing. :-)

Holding the vol+, vol-, and power keys while connecting your phone via USB to your computer will put it in download mode (windows machines only) 

@getting over it

Will they connect by bluetooth or through any connection wire? 

No i don't know 

In order to assess the bidirectional RF strength and coverage levels between the MX40 and the Access Points

Will the connection be made by Bluetooth or through some other type of connection wire?