ZyXEL Communications 642R Series manual Glossary

	Prestige 642R Series ADSL Router
10BaseT	Glossary
	The 10-Mbps baseband Ethernet specification that uses two pairs of twisted-pair cabling
ADSL	(Category 3 or 5): one pair for transmitting data and the other for receiving data.
	Asymmetrical Digital Subscriber Line is an asymmetrical technology, meaning that the
	downstream data rate is much higher than the upstream data rate. ADSL operates in a
	frequency range that is above the frequency range of voice services, so the two systems can
ARP	operate over the same cable.
	Address Resolution Protocol is a protocol for mapping an Internet Protocol address (IP
Backbone	address) to a physical machine address that is recognized in the local network.
	A high-speed line or series of connections that forms a major pathway within a network.
Bandwidth	This is the capacity on a link usually measured in bits-per-second (bps).
Bit	(Binary Digit) -- A single digit number in base-2, in other words, either a 1 or a zero. The
Byte	smallest unit of computerized data.
	A set of bits that represent a single character. There are 8 bits in a Byte.
CDR	Call Detail Record. This is a name used by telephone companies for call related information.
CHAP	Challenge Handshake Authentication Protocol is an alternative protocol that avoids sending
Client	passwords over the wire by using a challenge/response technique.
	A software program that is used to contact and obtain data from a Server software program
	on another computer. Each Client program is designed to work with one or more specific
	kinds of Server programs, and each Server requires a specific kind of Client. A Web Browser
Crossover	is a specific kind of Client.
	A cable that wires a pin to its opposite pin, for example, RX+ is wired to TX+. This cable
Ethernet	connects two similar devices, for example, two data terminal equipment (DTE) or data
Cable	communications equipment (DCE) devices.
CSU/DSU	Channel Service Unit/Data Service Unit. CSUs (channel service units) and DSUs (data
	service units) are actually two separate devices, but they are used in conjunction and often
	combined into the same box. The devices are part of the hardware you need to connect
	computer equipment to digital transmission lines). The Channel Service Unit device connects
	with the digital communication line and provides a termination for the digital signal. The Data
	Service Unit device, sometimes called a digital service unit, is the hardware component you
	need to transmit digital data over the hardware channel. The device converts signals from
	bridges, routers, and multiplexors into the bipolar digital signals used by the digital lines.
DCE	Multiplexors mix voice signals and data on the same line.
	Data Communications Equipment is typically a modem or other type of communication
	device. The DCE sits between the DTE (data terminal equipment) and a transmission circuit
DHCP	such as a phone line.
	Dynamic Host Configuration Protocol automatically assigns IP addresses to clients when they
	log on. DHCP centralizes IP address management on central computers that run the DHCP
	server program. DHCP leases addresses for a period of time which means that addresses are
DNS	made available to assign to other systems.
	Domain Name System links names to IP addresses. When you access Web sites on the
	Internet, you can type the IP address of the site or the DNS name. When you type a domain
	name in a Web browser, a query is sent to the primary DNS server defined in your Web
	browser’s configuration dialog box. The DNS server converts the name you specified to an IP
	address and returns this address to your system. From then on, the IP address is used in all

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