NetComm NB9 User Giude page 76

TCP/IP
Telnet
TFTP
TTL
twisted pair
upstream
USB
VC
VCI
VPI
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YML790 Rev1
Transmission Control Protocol/Internet Protocol The basic
protocols used on the Internet. TCP is responsible for di-
viding data up into packets for delivery and reassembling
them at the destination, while IP is responsible for deliv-
ering the packets from source to destination. When TCP
and IP are bundled with higher-level applications such as
HTTP, FTP, Telnet, etc., TCP/IP refers to this whole suite of
protocols.
An interactive, character-based program used to access a
remote computer. While HTTP (the web protocol) and FTP
only allow you to download files from a remote computer,
Telnet allows you to log into and use a computer from a
remote location.
Trivial File Transfer Protocol. A protocol for file transfers,
TFTP is easier to use than File Transfer Protocol (FTP) but
not as capable or secure.
Time To Live A field in an IP packet that limits the life
span of that packet. Originally meant as a time duration,
the TTL is usually represented instead as a maximum hop
count; each router that receives a packet decrements this
field by one. When the TTL reaches zero, the packet is
discarded.
The ordinary copper telephone wiring long used by tel-
ephone companies. It contains one or more wire pairs
twisted together to reduce inductance and noise. Each
telephone line uses one pair. In homes, it is most often
installed with two pairs. For Ethernet LANs, a higher
grade called Category 3 (CAT 3) is used for 10BASE-
T networks, and an even higher grade called Category
5 (CAT 5) is used for 100BASE-T networks. See also
10BASE-T, 100BASE-T, Ethernet.
The direction of data transmission from the user to the
Internet.
Universal Serial Bus A serial interface that lets you con-
nect devices such as printers, scanners, etc. to your com-
puter by simply plugging them in. The My ADSL Modem is
equipped with a USB interface for connecting to a stand-
alone PC.
Virtual Circuit A connection from your ADSL router to your
ISP.
Virtual Circuit Identifier Together with the Virtual Path
Identifier (VPI), the VCI uniquely identifies a VC. Your
ISP will tell you the VCI for each VC they provide. See
also VC.
Virtual Path Identifier Together with the Virtual Circuit
Identifier (VCI), the VPI uniquely identifies a VC. Your ISP
will tell you the VPI for each VC they provide. See also
VC.
NB9/NB9W ADSL2+ VoIP Router