User's Guide for ZyXEL Omni 56K USB Modem
EFCC The FCC (Federal Communications Commission) is in charge of allocating the
electromagnetic spectrum and thus the bandwidth of various communication systems.
FIFO-Buffer First-in-first-out buffer. A buffer of this type is used in the 16550 type UARTs that allow
higher data throughput rates on PCs.
Firmware The ZyXEL modems' system software is located in flash EPROMs. Depending on the size
of the EPROM(s), some features may or may not be available.
Flash Memory The nonvolatile storage that can be electrically erased and reprogrammed so that data can
be stored, booted, and rewritten as necessary.
Flow Control Method to stop and start the data flow to avoid loss of data.
Front Panel The front panel on the ZyXEL modems consists of LED indicators and key switches.
FSK Frequency Shift Keying – a frequency modulation scheme.
Full-duplex Transmission link where transmission can take place in both directions simultaneously.
G3 Fax Several fax standards exist. Most available fax machines use the Group 3 (G3) standard.
This standard defines the compression of graphic data and a transmission speed of up to
14400 bps with an automatic fallback to 2400 bps if the telephone line is bad.
Gateway A gateway is a computer system or other device that acts as a translator between two
systems that do not use the same communication protocols, data formatting structures,
languages, and/or architecture.
Handshake At the beginning of a connection, the modems must negotiate and initialize the protocols to
be used and the speed at which the connection is to be established. This negotiation phase
and the following initialization phase is called handshake.
HDLC HDLC (High-level Data Link Control) is a bit-oriented (the data is monitored bit by bit),
link layer protocol for the transmission of data over synchronous networks.
High-speed
Modem A modem that works at bit rates higher than 9600 bps.
Hook-Flash The hook-flash is a signal used in a dial sequence. This signal may be used for call transfers
or to request an outside line on certain PABX.
Host Any computer on a network that is a repository for services available to other computers on
the network. It is quite common to have one host machine provide several services, such as
WWW and USENET.
HTTP Hyper Text Transfer Protocol. The most common protocol used on the Internet. HTTP is
the primary protocol used for web sites and web browsers. It is also prone to certain kinds
of attacks.
Hz Hertz. A unit of measurement for frequency. Cycles per second.
Inside Wiring Wiring that is done from the point of demarcation to the jack in the wall where the line
terminates.
internet (Lower case i) Any time you connect 2 or more networks together, you have an internet.
Internet (Upper case I) The vast collection of inter-connected networks that all use the TCP/IP
protocols and that evolved from the ARPANET of the late 60’s and early 70’s. The Internet