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Internal Internet Service Commands
The modem has an embedded TCP/IP stack that is driven by AT commands and enables the host
application to easily access the Internet. The advantage of this solution is that it eliminates the need
for the application manufacturer to implement their own TCP/IP and PPP stacks, thus minimizing cost
and time to integrate Internet connectivity into a new or existing host application. This Section is a
reference guide to all the AT commands and responses defined for use with the TCP/IP stack. Access
is provided to the following Internet Services:
1. Socket Client and Server for TCP, Client for UDP
2. FTP Client
3. HTTP Client
4. SMTP Client
5. POP3 Client
Step-by-step instructions on how to configure and use TCP/IP communications:
•
First of all, create a connection profile with AT^SICS. The connection profile is a set of basic
parameters which determines the type of connection to use for an Internet service. Up to 6
connection profiles can be defined, each identified by the <conProfileId>.
•
Secondly, use AT^SISS to create a service profile based on one of the connection profiles. Up to
10 service profiles can be defined, each identified by the <srvProfileId>. The service profile
specifies the type of Internet service to use, i.e. Socket, FTP, HTTP, or one of the email services
SMTP or POP3. To assign a connection profile to a service profile, the <conProfileId> of AT^SICS
must be entered as "conId" value of the AT^SISS parameter <srvParmTag>. This offers great
flexibility to combine connection profiles and service profiles. For example, you may have one
connection profile (CSD or GPRS) specified with AT^SICS which can be associated with an SMTP
service profile for sending emails and a POP3 service profile for retrieving emails.
•
Once the connection profile and the service profile are created, an Internet session can be opened
by entering the AT^SISO write command and the desired <srvProfileId>. Wait for the resulting
URC.
•
The next command determines the action to be performed, for example reading data with
AT^SISR or writing data with AT^SISW. Wait for the resulting URC.
•
Finally, to end a session, enter the AT^SISC write command and the <srvProfileId>.
Maximum number of profiles defined / used:
•
Up to 6 connection profiles can be created (with AT^SICS).
•
Up to 10 service profiles can be created (with AT^SISS), but the number of parallel profiles of the
same service type is limited as listed below. If the maximum number of a service profile type is
already defined, any attempt to set up another profile for the same type will be denied with
"+CME ERROR: unknown".
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Maximum 3 HTTP profiles
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Maximum 6 socket profiles: Only 2 instances can be opened for listener, meaning that if 2
listeners are established another 4 instances can be opened for clients. Also, the socket
service can accept an incoming connection only when at least one service profile is still free
(not yet created with AT^SISS), otherwise the incoming connection will be rejected from the
listener. If there is no listener established all 6 socket profiles can be configured as client.
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1 FTP profile
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1 POP3 profile
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1 SMTP profile
