?
Solved

How to parse AT command

Posted on 2011-09-27
3
Medium Priority
?
3,555 Views
Last Modified: 2012-05-12
I'm starting a project that create a virtual modem. The modem receive an AT command and response it follow the command. But I don't know (don't have the idea) to parse the AT command to cover all of the cases.Anyone have the source code or document relate how to parse AT command using C language please suggest me. Thanks so much.
0
Comment
Question by:nnemo33
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 13

Accepted Solution

by:
Hugh McCurdy earned 2000 total points
ID: 36712837
Do you have the AT command set?  If not, I found this -- http://en.wikipedia.org/wiki/Hayes_command_set

I don't have code for you but I have a plan.  I would treat the commands as a tree an implement using mostly switch statements.  I would also use if statements near the bottom as applicable.  Here's an example of the top.  This is assuming that I've already determined the first two characters were indeed AT.

pCh is a pointer to the 3rd character at this point in execution.

switch ( *pCh )
{
    case 'A':
        Third_A ( pCh + 1 );
        break;

    case 'D':
        Dial ( pCh + 1 );
        break;

......

}


function Third_A ( char *pCh )
{
    switch ( *pCh )
    {
        case '0':
        case '\0':
            AnswerCall();
            break;

        case '/':
            RepeatLastCommand();   // Somehow you'd have to know what this is.  I have ideas if you don't.
            break;

        default:
            ErrorHandlerForUnknownCommand();
            return -1;
    }

    return 0;
}

Open in new window



As I think about the problems, it occurs to me that C++ might be a better choice.  But that's up to you.
0
 
LVL 8

Expert Comment

by:ssnkumar
ID: 36889949
Have you looked at mgetty and vgetty - that is an opensource software related to modem, fax, etc.
You can look at it at: http://mgetty.greenie.net/
0
 
LVL 8

Expert Comment

by:ssnkumar
ID: 36889961
Here is a page regarding "Controlling your Modem with AT Commands": http://www.zoltrix.com/support_html/modem/usemodem.htm

You can see the implementation of "Linux Generic Soft Modem" at: http://bellard.org/linmodem.html
The above software has a AT command parser.

And also, you can refer the following link to look at "Simple Hayes AT Command Parser": http://embeddedfreak.wordpress.com/2008/11/03/simple-hayes-at-command-parser/
0

Featured Post

Learn how to optimize MySQL for your business need

With the increasing importance of apps & networks in both business & personal interconnections, perfor. has become one of the key metrics of successful communication. This ebook is a hands-on business-case-driven guide to understanding MySQL query parameter tuning & database perf

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Outsource Your Fax Infrastructure to the Cloud (And come out looking like an IT Hero!) Relative to the many demands on today’s IT teams, spending capital, time and resources to maintain physical fax servers and infrastructure is not a high priority.
Not everyone has adapted to a rapid advancement in technology; there are people who are reluctant or afraid to delve into this brave new world of IT. If you have a friend or a family member who suffers from the so-called technophobia, here is how yo…
The goal of this video is to provide viewers with basic examples to understand how to use strings and some functions related to them in the C programming language.
Sending a Secure fax is easy with eFax Corporate (http://www.enterprise.efax.com). First, Just open a new email message.  In the To field, type your recipient's fax number @efaxsend.com. You can even send a secure international fax — just include t…

764 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question