Sierra Wireless DART 200 CDPD Modem - Manual (Page 147)

DART 200 CDPD Modem User’s Guide F DART AT Command Set
PN1197-00 Revision 1.0 F-3
Table F-1. Commands beginning with letters (cont.)
D (cont.) For a DART server the initial incoming datagram causes a RING message to be generated. If the auto
answer is not specified by setting S-Register 0=1, the Ring message is repeated every 10 seconds for
a total of 60 seconds.
If the call is not answered by the server (either automatically or with an ATA) the client is not
informed. However, for a DART UDP server the connection request (and the attached data packet)
remains pending. If an ATA is subsequently issued, UDP generates both a RING and a CONNECT
message and accepts the pending data packet.
If the client's connection request is accepted (TCP), or validated successfully (UDP) a CONNECT
message is generated, the DART enters online mode and is ready to begin communicating with the
server. Any concatenated commands on the same line are ignored. If input is detected prior to
entering online mode the command is aborted.
The destination address can be explicitly given on the command line or can be a stored address string
retrieved from the modem’s Dial Directory (see the S dial modifier below).
Format:
ATDs
s = dial string, plus optional dial modifiers. The dial modifier can precede (T,
P), replace (S), or follow (;) the dial string.
The dial string consists of a destination address (IP address) followed by an optional port number. It
is preceded, and optionally followed, by a dial modifier (see below). The port number, if present, is
separated from the IP address by a forward slash (/). If not present the port number for both the T
(TCP) and P (UDP) dial modifiers default to 23, the standard telnet port .
NOTE:
A DART modem in server mode only accepts calls directed to its listening port (see the *L
command). The default listening port is 2100, which is incompatible with the default dial port (23).
An example of a valid TCP dial string for port 2100 is ATDT123.456.789.2/2100.
Dial modifiers:
Dial modifiers allow additional information or actions to be specified during the connection
origination process. Dial modifiers include T; P; Sn and semi-colon (;).
T The T modifier enables a TCP connection to be established. The configuration of
the destination address string, as described above, still applies. The T modifier is
the default setting if no modifier is specified. Refer to Chapter 5, DART
Supported Protocols, TCP, for more information on TCP operation
Format:
ATDTs s = destination address string
P The P modifier prepares the DART for UDP communication. The configuration
of the destination address string, as described above, still applies. A CONNECT
response only means that the command was accepted, and that the addressing
information was saved to build UDP packet headers for the data that follows. To
actually communicate the destination must have a UDP server function active,
and the source must pass some application data to the DART for transmission.
If a DART defined as a server also acts as a client, the destination port number for
any originated calls must be different from the modems listening port if
backwards compatibility was specified. Refer to Chapter 5, DART Supported
Protocols, UDP, for more information on UDP operation.