Rocktron MIDI Xchange User Manual
Page 21
HOW TO USE THE CC17 and CC7 PORTS:
Connections - when using the Rocktron HEX Volume/Expression
pedal use a stereo to stereo 1/4 jack cable (not included). When
using a pedal other than the HEX you wil need two mono 1/4 male
jacks to a RTS1/4 stereo male Y-Cord - there are several different
kinds of expression pedal cables a few are shown below: