PEQs are usually 3 band minimum, the better PEQs being 5 band or more in some cases. Each band should allow you to specify a center frequency, the amount of Q (band width), gain, and slope.
OK Bob, you got me there 
. The PEQs I've owned and used had frequency, Q, and gain, but "slope"? Did you you mean "peaking/shelving" on the upper and lower bands perhaps? Digital PEQs will sometimes give you a choice of peaking/shelving/HPF. In the case of a HPF (or LPF) a slope of x dB/8ve might also be selectable, although I have yet to see it.
GTD
Oh that's a PEC for peculiar EQ...
JR
PS: I did a console back in the '70s with 4 band PEQ with switchable peaking/shelving on high and low bands.. that was an odd duck with with variable Q on the shelfs...It probably makes sense to disable the Q on the shelving sections. I didn't have enough switch poles.
