Boca Bocamodem M144EW, User Manual

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14.4Kbps BOCAMODEM
communications protocol . A set of procedures which controls how a
data communications network operates.
D
DCD . Data Carrier Detect. Indicates to the terminal device that the
modem is receiving a valid carrier signal from a remote modem. The
carrier is a tone at a specified frequency.
DCE . Data Communications Equipment. The local and/or remote
modem. A DCE is usually connected to a DTE.
DTE . Data Terminal Equipment. The computer or terminal, either
local (yours), or the remote (the one you’re communicating with). A
DTE is usually connected to a DCE.
DTR . Data Terminal Ready. The computer issues this signal to the
attached modem indicating that it is ready to receive data.
data compression . A technique that examines transmitted data for
redundancy and replaces strings (groups) of characters with special
codes which the receiving modem interprets and restores to its
original form. Transmission of compressed data results in shorter
connect times and hence cost savings for connect charges. Data
compression is sometimes called “source encoding”.
data mode . The modem is in data mode when a connection has been
established with a remote modem and sends a CONNECT response
confirming the connection. User data may then be transmitted or
received.
dial modifier . Dial modifiers are special characters appended to the
ATD command which instruct the modem how to place a call.
digital signa
l. A discrete signal which can only take on one of several
(usually only two) discrete levels in contrast to analog signals which
can take a continuous range of levels.