A cable isolator is provided for automatically performing cable breaks for testing of host bus adapters. A workstation includes a host bus adapter, such as a Fibre Channel storage controller, to be tested. The host bus adapter is connected to one or more storage modules through the cable isolator. The cable isolator includes two transceivers, one of which is connected to the host bus adapter and the other being connected to the storage modules. The two transceivers are also connected to each other internally. The cable isolator also includes a programmable logic device or controller that is used to enable and disable the two transceivers at set intervals. The one or more output disable signals are then provided to the transceivers to perform the cable break. The cable isolator may be an expansion card installed within the workstation. Thus, the workstation may communicate with the cable isolator through an expansion bus. The workstation may have a cable isolator driver and software application installed thereon. An operator may set periodic on-time and off-time values through the cable isolator software application. The workstation may then control the programmable logic device through the expansion bus. The cable isolator may also include memory and a programmable read-only memory to allow the cable isolator to operate autonomously. Thus, a program may be loaded into the memory on the cable isolator and the program may run without using the resources of the workstation.