Siemens AC75 Benutzerhandbuch

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AC75_ATC_V01.002

Page 253 of 569

10/30/06

Confidential / Released

AC75 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 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: 

Socket Client and Server for TCP, Client for UDP 

FTP Client 

HTTP Client 

SMTP Client 

POP3 Client 

The AC75 offers two modes of controlling an Internet session opened with 

. To select the mode that

best suits the preferences of your application design use the 

 command, parameter "Tcp/WithURCs"

(refer to 

• URC mode (delivery default):

The progress of an Internet session is URC driven. The URCs notify the host whether data can be sent or

received, whether data transfer has completed, whether the service can be closed or whether an error has

occurred. This mechanism eliminates the need to poll the service until the necessary progress information is

received.

To enable the URC mode select: 

="Tcp/WithURCs",on. 

• Polling mode:

In polling mode, the presentation of URCs related to the Internet Services is disabled. The host is responsible

to retrieve all the status information needed for controlling the Internet session. This is done by polling, where

the host application keeps sending the commands 

. 

To enable the polling mode select: 

="Tcp/WithURCs",off.

The disabled URCs are the following: "

" URC, "

" URC and "

" URC for parameter 

=0 (Internet service events), but not for 

=1 or 2 (needed for Socket listener and always

enabled). 

Step-by-step overview of how to configure and use TCP/IP communications with AC75: 
• Select URC mode or polling mode as described above. 
• First of all, create a CSD or GPRS connection profile with 

. The connection profile is a set of basic

parameters which determines the type of connection to use for an Internet service. The connection type is

also referred to as bearer. Up to 6 connection profiles can be defined, each identified by the 

. 

• Secondly, use 

 to create a service profile based on one of the connection profiles. Up to 10 service

profiles can be defined, each identified by the 

. 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 

 of 

 must be entered as "conId" value

of the 

 parameter 

. 

This offers great flexibility to combine connection profiles and service profiles. For example, you may have

one connection profile (CSD or GPRS) specified with 

 which can be associated with an SMTP ser-

vice 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 

 write command and the desired 

. 

In URC mode, the "

" URC indicates whether the service is ready to receive or send data.

This means, that the 

 or 

 command shall be entered after the URC was received. If an error

occurs the "

" URC is delivered instead. 

In polling mode, you can enter the 

 or 

 command straight after 

 though you may