Abstract: A system and method for isolating data messages received from subscribers in a CATV system are disclosed. The system includes a spectrum parallel router which receives data messages in the return spectrum of a service line at a service site. A switch at the service site directs data messages to service lines coupled to the site which have destination addresses corresponding to one of the service lines. Data messages not having a destination address corresponding to one of the service lines are provided to a transmitter for transmission to the next higher level of the CATV network over a return cable. Each service site has its own return cable which may be coupled to a distribution hub or a headend. At the distribution hub and headend, a switch is provided for each return cable and the switches are coupled to one another. At a distribution hub, data messages having a destination address corresponding to one of the other switches at the hub are routed to the corresponding switch.