The six pins in the back are from left to right:
(have to look it up to be sure though)1
3 expression pedal neg.
4 expression pedal pos.
5 +9v DC
6 audio out
Yes, you have read correctly,... expression pedal
I own almost all the **-01 series pedals and a SB 40 "system board" wich can hold 4 pedals.
The expression pedal input on the Flanger controls the "manual" knob on the pedal.
It's a great analog flanger (I have two of them, for stereo), The chorus is awesome two (can be modded to a kick ass chorus/vibrato).
You've probably also figured out this flanger self-oscillates when feedback gets beyond 7/8, used with a bit of delay and a large reverb it get's pretty eerie...
Also try a ring-mod like setting
depth 0 rate 0 feedback 7 manual 0/10.
Lots of weird effects lie within!