User's Guide for ZyXEL Omni 56K USB Modem
Fnow (July 1995) connects roughly 60,000 independent networks into a vast global internet.
Interrupt In a computer, some tasks must be performed regularly and without delay. This is possible
because the CPUs provide special interrupt vectors. These vectors each point to some short
program sequence. An interrupt stops the currently running program and the segment to
which the vector points is executed.
Intranet A private network inside a company or organization that uses the same kinds of software
that you would find on the public Internet, but that is only for internal use.
IP Internet Protocol. The IP (currently IP version 4, or IPv4), is the underlying protocol for
routing packets on the Internet and other TCP/IP-based networks.
IRC Internet Relay Chat. IRC was developed in the late 1980s as a way for multiple users on a
system to “chat” over the network. Today IRC is a very popular way to “talk” in real time
with other people on the Internet. However, IRC is also one avenue hackers use to get
information from you about your system and your company. Moreover, IRC sessions are
prone to numerous attacks that while not dangerous can cause your system to crash.
ISP Internet Service Providers provide connections into the Internet for home users and
businesses. There are local, regional, national, and global ISPs. You can think of local ISPs
as the gatekeepers into the Internet.
ITU-TSS International Telecommunications Union – Telecommunication Standards Sector. New
name for the standard making organization CCITT. See CCITT.
Jack Type Different types of jacks (RJ11, RJ45, or RJ48) can be used for an ISDN line. The RJ11 is
the most common in the world and is most often used for analog phones, modems, and fax
machines. RJ45 and RJ48 are essentially the same, as they both have the same 8-pin
configuration. An RJ11 jack can fit into an RJ45/RJ48 connector, however, an RJ45/RJ48
cannot fit into an RJ11 connector.
LAN Local Area Network is a shared communication system to which many computers are
attached. A LAN, as its name implies, is limited to a local area. This has to do more with
the electrical characteristics of the medium than the fact that many early LANs were
designed for departments, although the latter accurately describes a LAN as well. LANs
have different topologies, the most common being the linear bus and the star configuration.
LAPM Link Access Procedure for Modems – a protocol that controls the handshake between two
modems.
LATA (Local Access and Transport Area): A geographic territory used primarily by local
telephone companies to determine charges for intrastate calls. As a result of the Bell
divestiture, switched calls that both begin and end at points within the LATA (intraLATA)
are generally the sole responsibility of the local telephone company, while calls that cross
outside the LATA (interLATA) are passed on to an Inter eXchange Carrier (IXC).
Layer Protocol A standard of the ISO (International Standards Organization) which defines everything
regarding data communications from the hardware to the screen display in seven levels.
LEC (Local Exchange Carrier): The local phone companies – either a Regional Bell Operating
Company (RBOC) or an independent phone company (e.g., GTE) – that provide local
transmission services.
LED Light Emitting Diode – a display element.