DCE—Data Communications Equipment. In data communications terminology, this is the “modem” side of a computer-to-modem connection. The transceiver COM1 and COM2 ports are set as DCE.
Decibel (dB)—A measure of the ratio between two signal levels. Frequently used to express the gain (or loss) of a system.
DES—Data Encryption Standard. More information on DES is available at
www.itl.nist.gov/fipspubs/fip46-2.htm.
DHCP—Dynamic Host Configuration Protocol. An Internet standard that allows a client (that is, any computer or network device) to obtain an IP address from a server on the network. This allows network administrators to avoid the tedious process of manually configuring and managing IP addresses for a large number of users and devices.
When a network device powers on, if it is configured to use DHCP, it contacts a DHCP server on the network and requests an IP address. The DHCP server provides an address from a pool of addresses allocated by the network administrator. The network device may use this address on a “time lease” basis, or indefinitely, depending on the policy set by the network administrator.
DNP3—Distributed Network Protocol 3. DNP3 is an industry-standard protocol that was initially created for communication between electrical substation devices. Today, this non- proprietary protocol is being widely adopted for a variety of other applications. Although DNP3 is typically employed in a client-server environment, this serial protocol is one of only a few that allow peer-to-peer communication between devices without the need for a host computer. It does this in the same way that IP supports peer-to-peer communication in an Ethernet environment.
Encapsulation—Process by which a complete data packet, such as MODBUS frame or any other polled asynchronous protocol frame, is placed in the data portion of another protocol frame (for example, IP) to be transported over a network.
Typically this action is done at the receiving end, before being sent as an IP packet to a network. A similar reversed process is applied at the other end of the network extracting the data from the IP envelope, resulting in the original packet in the original protocol.
Endpoint—Ethernet or IP data equipment connected to the ports of the transceiver.
Fade Margin—The greatest tolerable reduction in average received signal strength anticipated under most conditions. Provides an allowance for reduced signal strength due to multipath, slight antenna movement or changing atmospheric losses. A fade margin of 15 to 20 dB is usually sufficient in most systems.
FHSS—Frequency Hopping Spread Spectrum. A common transmission technique used by license-free transceivers.
9-2 TranSphere TS Wireless Extended Range IP Networking Transceivers – January 2008 GFK-2489
