User guide

Developers guidelines | AT commands
340 June 2010
This is done by a converter which samples the signal voltage several thousand times
per second. Each sample is converted into a binary number which represents the
voltage at that instant, for example, 10011010, and the binary numbers are sent as a
serial stream down the digital network.
DSR
Data Set Ready. An EIA232 signal sent from the modem to the computer, usually
indicating that the modem is ready to establish a connection.
DTE
Data Terminal Equipment. The equipment that provides data, such as a computer or
terminal.
DTMF
Dial Tone Multi-Frequency
DTR
Data Terminal Ready. An EIA232 signal sent from the computer to the modem, usually
indicating that the computer is ready to begin communication.
EIA
Electronics Industries Association. A U.S. based group that forms technical standards
and coordinates ITU-TCCITT activities in the United States.
EMAE
End Mobile Accessory Equipment
EOL
End of line
EOP
End of page
EOM
End of message
Escape code
A series of three consecutive characters (default is +++) sent to the modem, causing it
to exit online data mode and enter online command mode.
Factory default settings
The profile configuration that is in effect when the modem is shipped from the factory.
Fax Class
Standards for fax transmission are set as classes. Class I and II allow data transfer
speeds ranging from 2400 bps to 9600 bps.
Final result code
A message sent from the modem to inform the PC that execution of an entered AT
command has been completed. Examples are OK and ERROR.
Flow control
The use of characters or EIA232 signals to start and stop the flow of data to avoid data
loss during buffering.