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Library for Decode/Encode SMS PDU

Eduard Gomolyako

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18 Oct 2012CPOL

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Library for decoding and encoding mobile short messages to/from SMS protocol data unit

Last Updates

You can find some community fixes mentioned on comments section on Project Home at Google Code[^].

Introduction

The smspdulib library is intended for more transparent interaction with SMS PDU. This thought over hierarchy of classes will allow you to create new classes for other types of short messages using the realized base functionality.

At present, the following types of short messages are supported: status report, SMS (with long (large) SMS parts support).

Hierarchy of Classes

Classes hierarchy

Sample Code

This example shows you how to decode PDU.

C#

SMSType smsType = SMSBase.GetSMSType(pduSource);
switch (smsType) {
    case SMSType.SMS:
        SMS sms = new SMS();
        SMS.Fetch(sms, ref pduSource);
        //Use instance of SMS class here
        break;
    case SMSType.StatusReport:
        SMSStatusReport statusReport = new SMSStatusReport();
        SMSStatusReport.Fetch(statusReport, ref pduSource);
        //Use instance of SMSStatusReport class here
        break;
}

This example show you how to encode SMS to PDU.

C#

SMS sms = new SMS();
sms.Direction = SMSDirection.Submited;
sms.PhoneNumber = &quot;+74951234567&quot;;
sms.ValidityPeriod = new TimeSpan(4, 0, 0, 0);
sms.Message = &quot;Me message here!&quot;;
string pduSource = sms.Compose(SMS.SMSEncoding.UCS2);

Useful Links

Updated

Updated Decode7bit method: Fixed some bugs (see comments)
PopDate method now doesn't recognize time zone because some phones send strange stuff

Please help me find more detailed specification of PDU format and TP-SCTS format.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

Eduard Gomolyako

Chief Technology Officer

Russian Federation

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Comments and Discussions

Re: Encoder/Decoder

uncleR18-Nov-09 1:19

18-Nov-09 1:19

Hi, the problem is in the Fecth() Function, it is not checking if validity period is not present.

You can fix it by doing this:

if (sms._direction == SMSDirection.Submited)
   if (sms._validityPeriod != 0x00) 
        sms._validityPeriod = PopByte(ref source);

Re: Encoder/Decoder

ummarbhutta21-Nov-09 4:49

21-Nov-09 4:49

You can download the new library with bug resolved from following link
http://forum.codeproblem.com/c/sms-sending-and-receiving-using-at-commands-in-c-with-support-of-long-sms/msg49/#msg49[^]

if any problem let me know Big Grin | :-D

Big Grin | :-D

Re: Encoder/Decoder

Member 305411522-Nov-09 22:44

22-Nov-09 22:44

Many Thanks

Re: Encoder/Decoder

ohinCZ24-Nov-09 0:02

24-Nov-09 0:02

This fix doesn't work for me. I am quite new to PDU, but for what I know I assume a typo. Didn't you want to test for _validityPeriodFormat?

if (sms._direction == SMSDirection.Submited)
{
  if (sms._validityPeriodFormat != 0x00)
    sms._validityPeriod = PopByte(ref source);
}

Re: Encoder/Decoder

Member 305411525-Nov-09 8:17

25-Nov-09 8:17

Your pdu doesn't support character like áà and ç. It would be great for you to add this type of characters to the decoding. Worldwide support from your library.

Updated version of this library

ummarbhutta18-Oct-09 8:03

18-Oct-09 8:03

I have uploaded a new verision of this library which supports 7-bit encoding as well as sending ling (multi part sms) using 7-bit encoding, have a look and have fun..
http://forum.codeproblem.com/c/sms-sending-and-receiving-using-at-commands-in-c-with-support-of-long-sms/msg38/. Big Grin | :-D

Big Grin | :-D

Suggestion/Doubts about receiving long SMS

faber7517-Oct-09 0:17

17-Oct-09 0:17

Hi, wonderful and helpful code.
I'm building an app that may receive lengthy messages and i have a few doubts.
I can recognize they are lengthy checking bool InParts and i can get current number with Part.
I can't get the total number of parts, because you use the 3rd header byte (that should contain the total parts number) for the InPartsID.
Is there something i'm missing ?
I changed your code for the InPartsID excluding _userDataHeader[3] from the evaluation, renamed the Part property to PartCurrent and created the property PartTotal as

    public int InPartsID
    {
        get
        {
            if (!InParts)
                return 0;

            return (_userDataHeader[2] << 8); // was return (_userDataHeader[2] << 8) + _userDataHeader[3];
        }
    }

    public int PartTotal
    {
        get
        {
            if (!InParts)
                return 0;

            return _userDataHeader[3];
        }
    }

public int PartCurrent
{
    get
    {
        if (!InParts)
        return 0;

        return _userDataHeader[4];
    }
}

In the tests that i'm doing is running just fine but PDU 'syntax' is new to me and i fear i'm missing something.
Sounds good to you ?

Thanks again for your code and for any suggestions you may give,
Fabrizio

Member 108861211-Oct-09 19:58

11-Oct-09 19:58

hi
thanks for sharing the nice article.
Iam new to the windows mobile development. I have requirement where in i have to send the SMS in binary format(8 BIT) via windows mobile 5.0 and 6.0 version. Iam using WinCE for this. Can you please help is there anyway i can acheive it.

Thanks,

Eduard Gomolyako11-Oct-09 23:30

Eduard Gomolyako

11-Oct-09 23:30

Hi, sorry, I have no experience in windows mobile development.

Best, Ed.

Open Source Project

KillerTiger20-May-09 10:37

20-May-09 10:37

Hi Ed,
I read your comments and one of them you wrote that you would create a open source project.
Have you already create?
If you had, could you tell us the url.
It would be a pleasure to help to increase this project.

Re: Open Source Project

Eduard Gomolyako20-May-09 19:33

Eduard Gomolyako

20-May-09 19:33

Welcome, http://code.google.com/p/sms-pdu/[^].

I think that I need your e-mail to add you to the project members.

Best, Ed.

Sending sms [modified]

tprimus8-Feb-09 21:31

8-Feb-09 21:31

Hi!

Reading sms work's fine!
I have problems with sending sms.
Can you say me what do i wrong?:

<br />
string pduSource = sms.Compose(SMS.SMSEncoding.UCS2);<br />
port.WriteLine("AT+CMGS=" + sms.Message.Length - 1 + "\r");   <br />
/* I become here the ">" answer<br />
port.WriteLine(pduSource + "\r");   <br />

Maybe i have to use other enconding type?

Thans for any suggestion.

Re: Sending sms

Member 47650628-Feb-09 22:37

8-Feb-09 22:37

Hi
The prob is the AT+CMGS length, all that is doing is counting the length of the text message, where it isnt that simple - i am in a similar situation trying to dynamically set the length based on the encoding/reciever/message etc myself at mo - so if anyone know... Wink | ;)

Wink | ;)

to test your length use this form:
http://twit88.com/home/utility/sms-pdu-encode-decode

Cheers

Simon

Re: Sending sms [modified]

Member 47650628-Feb-09 23:08

8-Feb-09 23:08

ok - it looks like you do a length count on the pdu output, removing the count of the pdu that is associated to the length of the smsc info... if someone can confirm that will be great - but this is what I am going to try, ans example below:

0011000A9121436587190000AA0BE8329BFD06D1D1657919 = hello there, sent to +1234567891

the first part 00 does not want to be counted - that leaves a total of 46 characters - 4 bit per char = 46/2 = 23

This is based on 7 bit encoding

Hope that helps, let me know if it works...

Simon

modified on Monday, February 9, 2009 5:17 AM

Re: Sending sms [modified]

tprimus9-Feb-09 6:48

9-Feb-09 6:48

Hi!

I try'd your example and that was the result:

<br />
AT+CMGS=23<br />
>0011000A9121436587190008AA1600680065006C006C006F002000740068006500720065<br />
+CMS ERROR: 304<br />

Maybe i have to setup the phone? (sony ericsson w880i)

at+cmgf=?<br />
+CMGF: (0)

modified on Monday, February 9, 2009 1:01 PM

Re: Sending sms [modified]

tprimus9-Feb-09 8:54

9-Feb-09 8:54

I found another encoder, and i know now, that after the message i have to put 0x1a

The following example is working from terminal window:

<br />
at+cmgs=15          <br />
> 07916302390090F911000B916302775625F20000FF0133<ctrl-z><br />
//<ctrl-z> = 0x1a HEX<br />
<br />
That way i try'd from my program:<br />
port.Write("at+cmgs=15" + "\r");<br />
/*<br />
...data received = ">"<br />
*/<br />
port.Write("07916302390090F911000B916302775625F20000FF0133" + 0x1a + "\r");<br />
/*<br />
...data received = "+CMS ERROR: 304"<br />
*/<br />

Pleaseeee HELP ME

D'Oh! | :doh:

D'Oh! | :doh:

Cry | :((

modified on Monday, February 9, 2009 3:08 PM

Re: Sending sms

nkachanov9-Feb-09 19:33

9-Feb-09 19:33

According to "SMS and the PDU format"[^] your PDU is 22 octets long, not 15.

Re: Sending sms [modified]

tprimus9-Feb-09 21:04

9-Feb-09 21:04

Its working in terminal window, thatway the length must be right.

I think the problem is with the closing character or the reading method...

Has someone a working sms sending example?

modified on Tuesday, February 10, 2009 3:18 AM

Re: Sending sms

nkachanov10-Feb-09 18:45

10-Feb-09 18:45

Not fully tested but worked for me:

port.NewLine = "\r\n";
port.ReadTimeout = 10000;
...
string pdu = sms.Compose(SMS.SMSEncoding.UCS2);
port.WriteLine("AT+CMGS=" + (pdu.Length / 2 - 1));
port.ReadTo("> ");
port.WriteLine(pdu + (char)0x001A);
port.ReadTo("+CMGS: ");
int msgRef = Convert.ToInt32(port.ReadLine());

Re: Sending sms

tprimus10-Feb-09 21:19

10-Feb-09 21:19

Works! Thank you!

nkachanov5-Feb-09 2:01

5-Feb-09 2:01

I believe I foud a bug in source code.
SMS.ValidityPeriod propery setter, line:
else if (value.Days > 1) //Up to 30 days
should be:
else if (value.Days >= 1) //Up to 30 days

Still the long message Problem

cam.artem4-Feb-09 21:34

4-Feb-09 21:34

Hi,
I don't know how to send a long message by this library.

I'm wondering about the UDH format and how to use it with my multipart message.

The library set the UDH with fixed bytes, but I really want to study this part.

Does anyone know where can I find the UDH spec?

Re: Still the long message Problem

nkachanov5-Feb-09 2:55

5-Feb-09 2:55

Hi,
I hope this will help:
http://en.wikipedia.org/wiki/Concatenated_SMS#PDU_Mode_SMS[^]
http://www.activexperts.com/activsms/sms/multipart/[^]

Re: Still the long message Problem

cam.artem5-Feb-09 18:10

5-Feb-09 18:10

Thank YOU!!!

I have a new question.

If I used UDH within my UserData field

how should I set UDL?

Re: Still the long message Problem

nkachanov6-Feb-09 4:08

6-Feb-09 4:08

Try to play with PDUSpy: Manual[^], Download here[^]

Example:
00 71 000B918702824744F44008C8 0C 05 0003FF0501 004600460046

As far as I understand, you have to place UDH (0003FF0501) and it's legth (05) at the beginning of the TP-UD and set TP-UDL to the total number of octets placed after it (0C).
Also you have to rise TP-UDHI flag of the first octet (see links in the article).

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