Comtech EF Data VMS v3.12.x Vipersat - Manual (Page 537)

Appendix H - Glossary H-5
MN/22156, rev 12
GIR Guaranteed Information Rate
Group ID A number assigned to equipment which defines it as a member of a group when
addressed by the VMS Hub Controller.
GUI Graphical User Interface – A form of graphical shell or user interface to a
computer operating system or software application.
H
H.323 A protocol standard for multimedia communications designed to support real-
time transfer of audio (such as voice over IP) and video data over packet
networks. Quality of Service is a key feature of H.323. An alternative to SIP.
HCC Hub Channel Controller – A dedicated Hub demodulator that has been desig-
nated as the ECM (ECMv2) controller, and which provides the TAP multicast
message to the Remotes.
HDLC High Level Data Link Control – A standard defining how data may be transmit-
ted down a synchronous serial link.
HPA High Power Amplifier – The amplifier used in satellite communications to raise
the transmit signal to the correct power level prior to transmission to satellite.
HTTP Hyper Text Transfer Protocol – The Internet standard for World Wide Web
(WWW) operation.
Hub The central site of a network which links to a number of satellite earth sites
(Remotes).
I
ICMP Internet Control Message Protocol
IDU Indoor Unit – In a VSAT system, the satellite modem is referred to as the IDU.
IF Intermediate Frequency – In satellite systems, IF frequencies are usually
centered around 70/140 MHz (video/TV), or 1200 MHz (L-band).
IFL Intra-Facility Link – The coaxial cabling used to connect the satellite ODU to
the IDU. Carries the inbound and the oubound signals, and the 24 VDC for the
LNB.