Application Note
Construction of SMS PDU’s
Page 1: ...Application Note Construction of SMS PDU s...
Page 2: ...obile Communications reserves the right to make modifications additions and deletions to this manual due to typographical errors inaccurate information or improvements to programs and or equipment at...
Page 3: ...MESSAGE REFERENCE FIELD TP MR 14 4 4 DESTINATION ADDRESS TP DA 14 4 5 PROTOCOL IDENTIFIER TP PID 15 4 6 DATA CODING SCHEME TP DCS 16 4 7 VALIDITY PERIOD TP VP 19 4 8 USER DATA LENGTH TP UDL 20 4 9 USE...
Page 4: ...This document is to help an integrator in getting started with sending SMS messages in the PDU format Enough information is given here for anyone to begin constructing the most basic PDU s and send t...
Page 5: ...nd structured when it sent over the air interface When we use a mobile phone we usually enter a text message by the keypad of the phone give it a phone number to be sent to press the YES button and us...
Page 6: ...tter to remove the SCA and work with TPDU only You may ask the question If a SMS must be sent via a Service Centre doesn t the SMS have to include the SCA The answer here is that the SCA is stored on...
Page 7: ...sentations The information in a PDU takes the form of pure hexadecimal integers decimal digits and alphanumeric information although still represented as hexadecimal For instance some fields in the PD...
Page 8: ...5C06 We can start by breaking it down into the various fields 4 1 The Service Center Address SCA 07916407058099F911000A8170607896200000A71554747A0E4ACF416 110945805B5CBF379F85C06 This is the Service C...
Page 9: ...numbering plan identification can be chosen according to the table below BIT NUMBER BIT VALUE EXPLANATION 7 1 ALWAYS Fill bit Type of number 0 0 0 Unknown 0 0 1 International number 0 1 0 National nu...
Page 10: ...ephone numbering plan And thirdly looking at the rest of the SCA we see that indeed we have an international number 46 705008999 46 being the dialing code for Sweden Looking closely at the SCA number...
Page 11: ...416 110945805B5CBF379F85C06 These fields are as follows 7 6 5 4 3 2 1 0 Reply Path TP RP User data header indicator TP UDHI Status report request TP SRR Validity Period format TP VPF Reject duplicates...
Page 12: ...he destination is unreachable before discarding the SMS There are 4 different choices for the validity period which can be chosen according to the following table BIT 4 BIT 3 MEANING 0 0 No Validity P...
Page 13: ...the GSM specification GSM 03 40 for the full details of how the User Data header can be used 4 2 6 Reply Path TP RP The reply path field is a 1 bit field in bit 7 of the octet in question This paramet...
Page 14: ...ce field TP MR This field is 1 octet in length and is just a hexadecimal representation of an integer reference number given to the SMS SUBMIT The number can range from 0 255 in value The user can set...
Page 15: ...bit 70 0 1 1 1 0 0 0 0 The digits 0 and 7 60 0 1 1 0 0 0 0 0 The digits 0 and 6 78 0 1 1 1 1 0 0 0 The digits 8 and 7 96 1 0 0 1 0 1 1 0 The digits 6 and 9 20 0 0 1 0 0 0 0 0 The digits 0 and 2 The Ad...
Page 16: ...to 00 For more information on the fields full properties and how to use it we refer you to GSM specification GSM 03 40 It may even be appropriate to contact your network operator for more information...
Page 17: ...for messages in this group and group 1100 For each indication supported the mobile may provide storage for the Origination Address which is to control the mobile indicator Text included in the user d...
Page 18: ...CS2 What about SMS classes There exists 4 different types of SMS classes and Classless SMS These classes can be simply described as follows Classless SMS This is usually the type sent by a mobile tele...
Page 19: ...phone understands only the GSM alphabet and will translate an 8 bit alphabet thus Try it and see 4 7 Validity period TP VP The Validity Period is the amount of time the Service Center will hold our su...
Page 20: ...then the TP UDL describes the number of characters or number of septets in the User Data field 2 If the User Data is 8 bit data or octet represented then the TP UDL describes the number of octets in t...
Page 21: ...ortunately we cannot directly replace each octet with a character instead we have to break the message down to the bit level and then translate over to the GSM character set First lets take a look at...
Page 22: ...to octets when we use the 7 bit alphabet Lets try to construct some user data by translating the word TEST to the hexadecimal representation Each letter shall be represented by 7 bits We can denote th...
Page 23: ...deconstruct our example User Data To do this we would have to perform the above procedure backwards The Data is 54747A0E4ACF416110945805B5CBF379F85C06 Now this is a long example so we won t do all of...
Page 24: ...632 R1A 24 1110011 s 0100000 space We have our first 8 characters in the message This is a PDU message Of course this could be simplified if one was to write a program to do the conversion Here ends t...
Page 25: ...s It will look like this 07916407058099F9040B916407752743F6000099012101758000155474 7A0E4ACF416110945805B5CBF379F85C06 We can now break it down into the various fields 5 1 Service Centre address This...
Page 26: ...sages waiting A value of 1 means there are no more messages are waiting at the Service Centre 5 2 3 Status Report Indication TP SRI This 1 bit field shows if a Status report will be returned to the or...
Page 27: ...re are no more messages waiting at the Service centre to be delivered to us Bits 3 and 4 as we already stated are set to 0 TP SRI is 0 and therefore a status report will not be returned to the origina...
Page 28: ...identical to the TP PID field described above in the SMS SUBMIT section We refer you to GSM specification GSM 03 40 for the full details 5 5 Data coding scheme TP DCS Again we have already discussed...
Page 29: ...ssion it is easy to see that each pair of digits are reversed and when rearranged give a date and time 99 01 21 01 75 80 00 pairing the digits 99 10 12 10 57 08 00 reversing the pairs So we see the da...
Page 30: ...ACF416110945805B5CBF379F85C06 Now we have seen the two most useful PDU formats For more details we refer you to the following GSM specifications GSM TS 03 38 V7 0 0 or later versions GSM TS 03 40 V7 1...
