A computer system, for example for use as a server, comprises a host processor, a service processor for providing system management functions within the computer system, and a user interface for receiving external commands and data for the service processor and/or the host processor, and for sending data from the service processor and/or the host processor. A device is provided for routing the commands and data to and from the user interface via the service processor only when the device receives a signal from the service processor. In the absence of the signal, the commands and data are sent between the user interface and the console interface bypassing the service processor. By this means, the host processor may be addressed even if the service processor malfunctions.