i need help with my radio. dont know what these dials do.

[blueb8llz]

hi, im trying to use my airtronics cx2p controller i found in my closet. but i lost my instruction manual and was wondering if you guys can tell me what these dials mean: this will be used for my 3905

E.P.A what does this do for the steering and throttle?
A.R.C what does this do for the steering and throttle?
SUB. T. what does this do for the steering?
and lastly, it has this switch i can either choose a.r.c or st? (under A.R.C it has a Q...and under the ST it has a M)