Comtech EF Data VIPERSAT File Streamer v1.2.x - Manual (Page 50)

A-6 VFS User Guide
be built into the motherboard, or be an expansion card. Some computers have
multiple NICs, each identified by a unique IP address.
NOC Network Operation Center (NOC) has access to any earth station installed using
the VIPERSAT Management System (VMS). A NOC can remotely interrogate,
control, and log network activities.
O
ODU Outdoor Unit – In a VSAT system the RF components (transceiver) are usually
installed outdoors on the antenna structure itself and are thus referred to as an
ODU.
OPEX Operating Expenditure
OSPF Open Shortest Path First – A common routing algorithm.
P
PLDM Path Loss Data Multicast message is sent every sixty seconds and
contains information on messages received or lost.
PMUX Port Multiplexing – Each port of the SDMS is individually configured from the
NMS port (hub) to port (remote) multiplexing.
PSTN Public Switched Telephone Network – Refers to the world’s public circuit-
switched telephone network governed by technical standards created by the
ITU-T, using telephone numbers for addressing. A mixture of digital and analog
telephone systems, the network includes mobile as well as fixed (land-line) tele-
phones.
Q
QPSK Quaternary Phase Shift Keying – A modulation technique in which the carrier
is phase shifted +/- 90 or +/-180 degrees. See also BPSK.