Cisco Cisco Explorer Set-top Software Version 2.1 User Guide
Glossary
749244 Rev G
245
GBAM
Global broadcast authenticated message. GBAMs provide a mechanism that allows IPPV
purchases to be secured. The combination of tokens required to purchase specific events.
HAL
Hardware adaptation library.
HDTV
high-definition television. The high-resolution subset of the DTV system.
headend
The location of the network elements that processes the signal by receiving and preparing the
source signals and making them ready for the transport network. See also network elements.
heap
A segment of memory used by a program.
horizontal resolution
The number of vertical lines (or pixels) that can be resolved from one side on an image to the
other side.
hub
Physical locations designed to serve a specific number of subscribers, usually 50 to 15,000.
May be co-located with the headend or miles away from the headend. Hubs receive,
modulate, and boost the signal prior to sending it to the network of HFC nodes for
distribution to the subscriber. Hubs usually contain QPSK modulalators/demodulators that
establish the two-way communications with the DHCTs.
I
inband
Interactive content sent as part of a broadcasted data stream (like MPEG-2).
Internet Protocol
The standard protocol within TCP/IP that defines the basic unit of information passed across
an Internet connection by breaking down data messages into packets, routing and
transporting the packets over network connections, then reassembling the packets at their
destination.
IP
See Internet Protocol.