Precidia ipocket232, User Manual

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23-CML000293 iPocket232 Inc. F-1
Appendix F:Modem connection
Control
Modem Connection Control is available with your product. The iPocket 232 is
slightly different since it is a DCE device and drives the DCD signal. When you
choose Modem as the method of Connection Control, the iPocket 232 behaves like
a Hayes, or “universal” modem to the device connected on its serial port. The
connected serial device (DTE) receives the expected modem replies when
communicating with the iPocket
232 . For further information on setting Modem
Connection Control, see “Connection Control” on page 27.
iPocket 232 Modem Overview
AT commands direct a modem to dial, answer, hang-up, and perform many other
communication tasks. All commands listed, except A/ and +++, must be preceded
by AT, followed by a carriage return. You can include multiple commands on a
command line, as long as the command does not exceed 80 characters when
including the prefix and carriage return. Spaces are ignored. Commands following a
command that opens, or closes an active connection, are ignored.
A Dial command (ATD) instructs the modem to attempt a connection to the
specified IP address and port number, or, if none is specified, to the configured
Remote IP in the Serial Port Settings sub-menu.
An On-Line command (ATO) instructs the modem to return to its active connection.
If there is no active connection, the modem attempts to establish one using the
configured Remote IP and Remote Port.
An Answer command (ATA) instructs the modem to listen on a specified port
number. If no port number is specified, the configured local port number is used. If
the local port is not set, the standard telnet port (23) is used.
The escape sequence (+++) causes the modem to return to command mode from
answer or dial states, keeping the active connection open. An on-off transmission on
the DTR line also causes the modem to return to command mode. In this case, the
active connection may be maintained or closed, depending on how AT&D2 is
defined.
The modem must be in command mode to receive commands. Any command, other
than the escape sequence (+++), that is sent to the modem while it is in transmission
mode, is transmitted as data.