OpenCable™ Unidirectional Receiver (OCUR) - (Tru2way) - The OCUR is a digital cable receiver with a tuner. It has CableCARD™ functionality and an IP (Internet Protocol) interface. It uses an IP connection and can hook to a Home Media Center.  It can be used by multiple users in different rooms.

This cable interface for Microsoft Vista-enabled personal computers initially supported one-way services (linear TV) while a two-way interactive interface was being developed.

www.opencable.com/specifications/ocur.html & this PDF file
www.opencable.com/downloads/ProcessOpenCableOCUR.pdf