User Manual

134 MDS entraNET 900 System Guide (Preliminary) MDS 05-4055A01, Rev. A
Data Communications Equipment—See DCE.
Data Terminal Equipment—See DTE.
dBi—Decibels referenced to an “ideal” isotropic radiator in free space.
Frequently used to express antenna gain.
dBm—Decibels referenced to one milliwatt. An absolute unit used to
measure signal power, as in transmitter power output, or received signal
strength.
DCE—Data Circuit-terminating Equipment (or Data Communications
Equipment). In data communications terminology, this is the “modem”
side of a computer-to-modem connection.
COM1 Port of the transceiver
is set as DCE.
Decibel (dB)—A measure of the ratio between two signal levels. Fre-
quently used to express the gain (or loss) of a system.
Device Mode—The operating mode/role of a transceiver (Access Point
or Remote) in a wireless network.
DHCP (Dynamic Host Configuration Protocol)—An Internet stan-
dard that allows a client (i.e. any computer or network device) to obtain
an IP address from a server on the network. This allows network admin-
istrators to avoid the tedious process of manually configuring and man-
aging IP addresses for a large number of users and devices. When a
network device powers on, if it is configured to use DHCP, it will con-
tact a DHCP server on the network and request an IP address. The
DHCP server will provide 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. The DHCP server can restrict allocation of IP
addresses based on security policies. An MDS NET 900 access point
may be configured by the system administrator to act as a DHCP server
if one is not available on the wired network.
Digital Signal Processing—See DSP.
DSP—Digital Signal Processing. DSP circuitry is responsible for the
most critical real-time tasks; primarily modulation, demodulation, and
servicing of the data port.
DTE—Data Terminal Equipment. A device that provides data in the
form of digital signals at its output. Connects to the DCE device.
Encapsulation—Process in 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 (in this case IP) to
be transported over a network. Typically this action is done at the receiv-
ing end, before being sent as an IP packet to a network. A similar re-