Ground Isolated Serial Connector by Neptune Systems. The ground isolated serial connector (SERIPC9) is used to break ground loops between your PC and the AquaController. In some installations a ground loop is formed when a serial connection is made and can cause erroneous pH and ORP readings. This ground loop can be broken by installing a GISC in the series with the serial cable from the AquaController. If the serial cable is going to be permantly hooked up to the AquaController, then the GISC is recommended. The GISC measures 1.5" x 1.25" x .65" and has one male DB9 connector and one female DB9 connector. Note that the GISC is only for use with the AquaController or the AquaController 2: the AquaController PRO has a built-in ground isolated serial connector.