I PMd ya with another link/ Almost looks like this was/is a 2 line model. Looks like a lot of ooptiions for how you want the phone to behave.
Anyway,
Here are the possibilities, depending on your model:
510A/B
R B SL/R S
-----------------
1 2 A K
L2 L1 A K
510 E/F
R B SL/R S
-----------------
1 2 A K
E1 E2 A A
L2 L1 A K
L2 L1 1 2
GN R L2 L1
I PM'd ya with a link to a schematic.