DigiTech CONTROL 2 Owner's Manual page 10

Rear Panel
Rear Panel
1 2
1. Processor Jack
Attach one end of the included Controller cable here. Connect the other
end to your GSP unit's Foot Controller port.
WARNING: Only connect the Control 2 Remote Foot Controller to
the GSP1101 or other DigiTech products which specify a connection to
the Control 2. Do not connect the Control 2 Remote Foot Controller
to Ethernet connections as damage will occur.
2. Expression 2 Input
Connect an optional expression pedal here using a 1/4" cable. A passive
expression controller or volume pedal is recommended.

Control 2 Owner's Manual