Cisco uBR900 Series Configuring page 137

Glossary
spectrum reuse—CATV's most fundamental concept. Historically, the over-the-air spectrum has
been assigned to many purposes other than that of carrying TV signals. This has resulted in an
inadequate supply of spectrum to serve the needs of viewers. Cable can reuse spectrum that is sealed
in its aluminum tubes.
subscriber unit (SU)—An alternate term for cable access router. See cable access router.
upstream—The set of frequencies used to send data from a subscriber to the headend.
Configuring the Cisco uBR900 Series Cable Access Routers 137