Auto-discrimination between FC and SATA devices upon insertion of a device into a port of a FAST-compatible switch is disclosed. Without user intervention, the port is able to determine the type of device attached, set the appropriate data rate in the Phy or SERDES and, in the case of FC or SATA drives, start the disk insertion process into the active switch zones. The SERDES is first initialized to FC speeds, and the receive path is searched for a receive signal. Upon detecting a receive signal, the detection circuitry then checks to see if a valid SATA Out Of Band (OOB) sequence is received. If a valid SATA OOB sequence is received, the SERDES is configured for SATA speeds and analog settings. If a valid SATA OOB sequence is not received, and instead a FC auto-negotiation process runs to completion, the SERDES remains at FC speeds.