User manual

Glossary
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P
PIN Personal Identification Number. A code number used to provide access to a system that has
restricted access.
PoE Power over Ethernet
POST Power On Self Test. A test sequence that runs every time the system is powered up or reset.
PPPoE Point-to-Point Protocol over Ethernet. A network protocol for encapsulating Point-to-Point
Protocol (PPP) frames inside Ethernet frames. By using PPPoE, users can virtually "dial" from
one machine to another over an Ethernet network, establish a point to point connection
between them and then securely transport data packets over the connection.
PS Packet-Switched. Packet-switched networks move data in separate, small blocks (packets)
based on the destination address in each packet.
PUK PIN Unblocking Key. An eight-digit code used to unblock a SIM card after three incorrect PINs
have been entered. The PUK code is supplied with the SIM card.
S
SAS Satellite Access Station. The gateway between the satellites and the worldwide networks such
as Internet, telephone network, cellular network etc.
SIM Subscriber Identity Module.The SIM provides secure storing of the key identifying a mobile
phone service subscriber but also subscription information, preferences and storage of text
messages.
SIP Session Initiation Protocol. An application-layer control (signalling) protocol for creating,
modifying, and terminating sessions with one or more participants. Used e.g. for Internet
telephony.
SMS Short Messaging Service
U
UTC Coordinated Universal Time. The International Atomic Time (TAI) with leap seconds added at
irregular intervals to compensate for the Earth’s slowing rotation. Leap seconds are used to
allow UTC to closely track UT1, which is mean solar time at the Royal Observatory, Greenwich.
V
VoIP Voice over IP. The routing of voice conversations over the Internet or through an IP-based
network.