An interface for a communications receiver such as a cable or satellite television receiver allows control between the receiver and an external device. The external device can supplement the services provided by the receiver. The interface includes a bidirectional control port for coupling the external device to the communications receiver. Ports for isochronous data and high speed data are also provided. The external device can simulate commands available via a user interface for the receiver, such as remote control actuations. In this manner, the external device can access information and control the receiver (e.g., to tune to a specific television or data channel) via the bidirectional control port. The interface enables the external device to use the full capabilities of the communication receiver for data acquisition and processing. The acquired and processed data is then delivered to the external device via the interface.