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User’s Guide AT Command Reference
2110212 Rev 1.0 Page 99
Table 12-1: AT Commands in CDPD Mode (continued)
Command Description
D [options]
Dial
Initiates a TCP or UDP PAD client session. This command is not supported in SLIP and PPP
mode. Results in SLIP/PPP are undocumented.
In PAD service modes, this is equivalent to ATO “go on-line”, turn on Data Carrier Detect
(DCD), and provide the packet service according to +WS45 (Packet Service). Command options
determine the destination address of the connection and the originating NEI account to use.
Options:
ip.port A Destination IP address and port are specified according to the following syntax:
[x.x.x.x[.y]] where x.x.x.x is a valid IP address (x has value 0 – 255) and y is a valid
port number. Friends Only does not impact client sessions. The modem may dial any
IP address whether or not it is in the Friends list.
Both the IP address and the port are technically optional, but the port is ignored if
specified without an IP address. If the IP address and/or port are not specified, then the
values of the last dial command will be used. However, there is no facility to read the
current default address and port. The host must track this or provide the address and
port explicitly with each dial. It is highly recommended that all dial commands
include the destination IP and port.
q q = 1 – 10. Quick dial using the IP and port values in the Friends List indexed by the
value q. This is an alternative to using the explicit ip.port option.
Notes:
In UDP and TCP modes, each new dial command will generate a packet source address consisting
of the modem’s registered NEI as the IP address and a port number for the session. The port
number is a pseudo-random number in the range of 1025 to 4999 and will remain fixed for the
duration of the session. Changing the port number with each new session allows the modem to
discard late-arriving packets when the earlier session has been closed.
If the modem was not registered when the Dial command is issued, it will attempt to register as
though a +WPREG command was prefixed to the dial.
In UPD, SLIP and PPP service +WS179 controls a registration wait status. If +WS179=0, the D
command goes immediately “online”, issuing the “CONNECT” result code and setting DCD
before completing the registration process. The modem remains “connected” even if registration
fails.
If +WS179 is non-zero, the D command waits for the modem to complete NEI registration, or for
+WS198 (Registration Wait Time) seconds to expire, before issuing a result code. If +WS198
expires, or registration fails, the modem issues the “NO CARRIER” result code and returns to
command state.
TCP service must complete the logical connection before CONNECT is issued regardless of the
setting of +WS179.
Result Codes:
OK Command is terminated with a semicolon (;) cancellation.
CONNECT normal response; the session is open.
NO CARRIER failed to register the NEI within time allowed.
NO ANSWER Only in TCP service, this indicates failure to complete the TCP handshake.
ERROR Invalid IP address, port, or unrecognized parameters are specified.
PAD ERROR A fault has occurred in the PAD service and the modem will have to be reset.