Specifications

Chapter 10 – Internet Service Commands
Multi-Tech Systems, Inc. AT Commands for EDGE Modems (S000371B) 121
Chapter 10. Internet Service
Commands
The Multi-Tech Wireless EDGE 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 its own TCP/IP and PPP stacks, thus minimizing cost and time to integrate
Internet connectivity into a new or existing host application. This chapter 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 with Multi-Tech Wireless
EDGE modem:
• First of all, create a connection profile with AT^SICS. The connection profile is a set of basic parameters that
determine 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”.
∗ - Maximum 3 HTTP profiles
∗ - Maximum 6 socket profiles: Only two instances can be opened for the listener. This means that if
two listeners are established another four 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 closed to the listener. If there
is no listener established, all six socket profiles can be configured as Client.
∗ - 1 FTP profile
∗ - 1 POP3 profile
∗ - 1 SMTP profile
• The TCP/IP stack of Multi-Tech Wireless EDGE modem supports using several service profiles at the same
time, provided all of them are running on the same connection profile. For example, it is possible to
download files from an FTP server, while sending and receiving emails at the same time.
• GPRS connections established over the Dial-Up Network do not use the embedded TCP/IP stack of Multi-
Tech Wireless EDGE modem and can be active at the same time. This allows the user to have two parallel
GPRS connections: for example for sending or receiving emails over a GPRS connection enabled by the
TCP/IP stack while, at the same time, surfing the Internet over a Dial-Up Network GPRS connection.