Gamry Instruments Reference 30k Booster Operator's Manual page 38

Panel Indicators, Controls and Connectors – Rear-panel Connectors
In the Reference 3000/Reference 30k Booster system, make this connection with a 25-pin D-to-25-pin D
cable, Gamry P/N 985-00120.
Caution:
The Gamry 985-00120 cable contains special shielding and grounding. Do not
substitute third-party 25-pin D-to-25-pin D cables for the Gamry cable.
38