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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

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).

Re: Still the long message Problem

cam.artem8-Feb-09 15:03

8-Feb-09 15:03

Thank you!!!

Great help!!!

Re: Still the long message Problem [modified]

cam.artem16-Feb-09 14:49

16-Feb-09 14:49

Excuse me~
I have another question.
About the first two bytes of UDH, as I saw the description on Wiki:

# Byte 00: Information Element Identifier, 00 for concatenated sms with 8-bit and 08 with 16-bit CSMS reference number
# Byte 01: Length of the header, excluding these two first bytes; always 3 (8-bit ref number) and 4 (16-bit ref number) for a CSMS
# Byte 02: 00-FF, CSMS reference number, must be same for all the SMS parts in the CSMS

when will we use byte00 for 08 and byte01 for 04 ?

I don't understand the meaning and usage of this CSMS ref number.

Is it related to AT+CSMS ??(what's the usage of this at cmd )

modified on Tuesday, February 17, 2009 4:09 AM

Re: Still the long message Problem

ummarbhutta17-Oct-09 8:19

17-Oct-09 8:19

This library doesn't seem to support multipart SMS Sending in 7bit.. I will soon upload the updated version of this library which will support multipart sms sending in 7bit encoding.

speaderDA20-Nov-08 13:44

20-Nov-08 13:44

Will your library support sending an SMS message to an e-mail address? Can you tell me how the e-mail address is imbedded into the message?

Re: SMS to e-mail

Eduard Gomolyako20-Nov-08 19:11

Eduard Gomolyako

20-Nov-08 19:11

Actually I don't understand what are you saying about, so I think the answer is NO.

Best, Ed.

Re: SMS to e-mail

speaderDA25-Nov-08 13:47

25-Nov-08 13:47

Looking at the library you have put together, I can see that I can send an SMS message to a phone number. What I would like to know is does your library support sending an SMS message to an email address?

Re: SMS to e-mail

Eduard Gomolyako25-Nov-08 19:24

Eduard Gomolyako

25-Nov-08 19:24

I understand, but I don't know how to decode email address in sms PDU. See links at the end of the article, may be you can find answer there.

Best, Ed.

Alphanumeric address decoding

benetnash8-Sep-08 3:31

8-Sep-08 3:31

Hi!
Could you update your code, to recognize alphanumerical addresses and decode it?
I used youd modified code for that:

public static string PopAddress(ref string source, int length)
       {
           string address = source.Substring(0, length);

           source = source.Substring(address.Length);

           byte addressType = PopByte(ref address);

           if (0x09 == addressType >> 4) {
               address = "+" + ReverseBits(address).Trim('F');
           } else if (0x0D == addressType >> 4) {
               /* alphanumeric address */
               address = Decode7bit(address, (int)Math.Truncate(address.Length * 4.0 / 7.0));
           } else {
               address = ReverseBits(address).Trim('F');
           }

           return address;
       }

Best regards
benetnash

Re: Alphanumeric address decoding

Eduard Gomolyako8-Sep-08 3:51

Eduard Gomolyako

8-Sep-08 3:51

Hi! Thank you for advice!

I think I will create an open source project on codeplex or google code and you will be able make changes by yourself.

Best, Ed.

Re: Alphanumeric address decoding

Audi Nugraha1-Dec-10 2:51

1-Dec-10 2:51

How do you get

(int)Math.Truncate(address.Length * 4.0 / 7.0)

?

Thanks in advance Big Grin | :-D

Big Grin | :-D

Could I use this library in C/C++ environment

John Yueh3-Sep-08 17:39

3-Sep-08 17:39

Hi there,

Can this library be use in C/C++ environment or could anyone suggest library/open source of this kind? Thanks!

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