Modules that convert Alternate Current (AC) power to Direct Current (DC) for the operation of electronic and computer equipment. Depending on the manufacturer and product, these modules can range from typical wall wart transformers that plug into a wall socket to larger, enterprise-level Power Over Ethernet systems that inject DC power into the Ethernet cables to provide power to the access points.
Glossary
DC power module
Device-to-device network
Two or more devices that connect using wireless network devices without the use of a centralized wireless access point. Also known as a peer-to-peer network. (See ad hoc mode, Peer-to-peer network).
DHCP
Dynamic Host Configuration Protocol. A protocol for dynamically assigning IP addresses from a pre-defined list to nodes on a network. When they log on, network nodes automatically receive an IP address from a pool of addresses served by a DHCP. The DHCP server provides (or leases) an IP address (to a client for a specific period of time. The client will automatically request a renewal of the lease when the lease is about to run out. If a lease renewal is not requested and it expires, the address is returned to the pool of available IP addresses. Using DHCP to manage IP addresses simplifies client configuration and efficiently utilizes IP addresses. (See IP address).
Dial-up
A connection to a remote network, or the Internet, using a standard modem and telephone connection, or Plain Old Telephone Service (POTS). (See POTS).
Diversity antenna
An antenna system that uses multiple antennas to reduce interference and maximize reception and transmission quality.
DNS
Domain Name Service. An Internet service that translates alphanumeric domain names to assigned IP addresses and vice versa. The term is typically used to describe the server which makes the translation. Every website has its own specific IP address on the Internet. DNS typically refers to a database of Internet names and addresses which translates the alpha-numeric names to the official Internet Protocol numbers and vice versa. For instance, a DNS server converts a name like mywebsite.com to a series of numbers like 107.22.55.26. (See IP, IP address).
DSL
Digital Subscriber Line. A dedicated digital circuit between a residence or business and a telephone company's central office. It allows high-speed data, voice and video transmissions over existing twisted-pair copper Plain Old Telephone Service (POTS) telephone wires. (See broadband, POTS).
Dual-band
A device that is capable of operating in two frequencies. On a wireless network, dual-band devices are capable of operating in both the 2.4 GHz (802.11b/g) and 5 GHz (802.11a) bands. In cellular phone technology, dual-band devices typically operate in both the GSM900 and GSM1800 frequencies, allowing a greater number of roaming options. (See Tri-mode).