Kramer Electronics PT-1FW PT-1FW is a line protector for FireWire signals. It is used in Plug and Play applications where constant plugging and unplugging of FireWire equipment can result in permanent damage to sensitive equipment due to ESD (electrostatic discharge). Passive - No power required. Input/Output - 2. ESD Protection - Incorporates Kramerfeets Spark-Guard ProTM signal protection circuitry to help protect against ESD (electrostatic discharge) which can damage digital equipment.