this time frame to prevent a drop in order to be effective switchover generally need not be transparent the degree to which data loss can be tolerated depends on the application at the very least the new resource must at least initially follow the same protocol as the old resource preferably this will also include using consistent frame numbering consistent error coding and consistent compression techniques fig1 illustrates a data communication interface 20 according to one embodiment of the present invention data bus 22 carries data for one or more data connections data handling resources 24 and 26 both connect to data bus 22 and communicate with resource controller 28 data handling resources 24 and 26 also connect to resource state memory 30 normal operation of the system is as follows data handling resource 24 participates in new data connections through data bus 22 as resource 24 develops internal state information about the operation of a connection it saves some of this information to resource state memory 30 meanwhile resource controller 28 remains ready to respond to conditions that warrant removal of the data connection from resource 24 data handling resource 26 sits ready to take over connections as required when a connection is to be switched from resource 24 to resource 26 resource controller 28 signals resource 26 as systems benefiting from the invention have the capability for multiple simultaneous data connections the signal should contain information appropriate to allow resource 26 to ascertain how to access data connection information from both resource state memory 30 and data bus 22.