A method and system for operating a bus according to a plurality of bus protocols, including a legacy bus protocol. A first signal is transmitted indicating a transaction request of a first kind. A second signal is transmitted indicating a transaction request of a second kind. The second signal may be decoded according to a plurality of protocols. The first signal is decoded prior to decoding the second signal. The decode of the first signal indicates which of the plurality of protocols should be used to decode the second signal. A computer system includes a bus, preferably an LPC bus, coupling two or more devices.