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The Wireless Messaging API (WMA) is an optional package for J2ME that
provides platform-independent access to wireless communication resources
like Short Message Service (SMS). If URI for HTTP is defined by http://
then URI for SMS resource is defined by sms://. Example resource identifier
for SMS is sms://:50000, means the port of SMS is 50000.

For example you have a J2ME application that listen to specific port, then
how to send SMS to the receiver would be this J2ME application? Simple approach
is to create another J2ME application that act as sms sender. But what is the
real PDU (protocol data unit) involved for sending it?

If you see GSM 03.40 specification, you will find that we need to set some
special UDH (user data header) inside the 140 octet of TP-UD. This UDH is like this
060504C3500000, the details is:
0×06 : TP-UDHL, means the user data header length -> length of “0504C3500000″ = 6 octet
0×05 : Application port addressing scheme, 16 bit address, means we have port range up
to 2^16 = 65536, so port 50000 is in the range
0×04 : Length of application port addressing scheme -> length of “C3500000″ = 4 octet
0xC350: Destination port, convert 0xC350 to decimal, you will have 50000
0×0000: Source port

For working example, please run this WMA java example taken from Sun JME toolkit
On the phone side we see that application is waiting for incoming SMS at port 50000

We’re now sending the SMS using AT+command, here’s the PDU:

55010A91560996658600F5A71F060504C3500000496E6920636F6E746F6820666C61736820534D53206C686F

To break down that PDU please refer to GSM 03.40 :), meanwhile I will focus on the 1st byte
that inform us that this PDU contain UDHI (user data header indicator) and the TP-UD of SMS
which is 1F060504C3500000496E6920636F6E746F6820666C61736820534D53206C686F

1F: TP-UDL (user data length)
060504C3500000 : this is the UDH (see above)
496E6920636F6E746F6820666C61736820534D53206C686F : this is the data

and here’s the screenshot at the mobile phone after receiving this SMS

Flash SMS is a type of SMS which will be displayed directly on screen once received. This one is known working on Nokia mobile phone, I don’t know with others. As we know, normal SMS once received is saved either on SIM card or mobile phone memory and then user is noticed by a beep or similar SMS alarm. Flash SMS is different.

Flash SMS is done by define message class part of TP-DCS of SMS PDU to zero (0×00), what TP-DCS is? Please read GSM 03.40 :). Here’s an example of SMS PDU (in hexadecimal):

15010A91561904472800F4A718496E6920636F6E746F6820666C61736820534D53206C686F

Let us breakdown:

• 1st byte: 0×15 or in binary 00010101
  • TP-MTI (bit 0&1) = 01 means this PDU SMS type is SMS-SUBMIT
  • TP-RD (bit 2) = 1 means reject duplicate if there’s a same SMS with same TP-MR
  • TP-VPF (bit 4&3) = 10 means this SMS contain validity period info with relative format
  • TP-SRR (bit 5) = 0 means we don’t ask for delivery report
  • TP-UDHI (bit 6) = 0 means no user data header information (UDHI)
  • TP-RP (bit 7) = 0 means reply path unused
• 2nd byte: TP-MR = 0×01, means message reference number is 0×01
• 3rd byte: TP-DA length = 0×0A, this is length of destination address.I want to send to my own number which is 6591407482 -> see there’re 10 digits, to TP-DA should be 0×0A or 10 in decimal
• 4th byte: TON/NPI info = 0×91 or in binary format 10010001
  • TON (bit 6,5,4) = 001 -> means International Number
  • NPI (bit 3,2,1,0) = 0001 -> means ISDN telephone number
• 5th byte .. 9th byte: 5619044728 -> this is the destination number 6591407482 but written in BCD semioctet format
• 10th byte: TP-PID = 0×00 -> means use default protocol identifier
• 11th byte: TP-DCS = 0xF4 or in binary format 11110100
  • Bit 3,2 = 01, means TP-UD (user data) is encoded using 8 bit format
  • Bit 0,1 = 00, means class 0 {this will make this sms become flash sms}
• 12th byte: TP-VP = 0xA7 means this SMS is valid only for 24 hours
• 13th byte: TP-UDL = 0×18 means the user data/message part length is 24 character
• the rest byte:
  • 496E6920636F6E746F6820666C61736820534D53206C686F
    • Thi is hex representation of string “Ini contoh flash SMS lho”, you may use http://www.ttdpatch.net/cgi-bin/str2hex.pl to convert from hex to string and vice versa

Now we try to send it using AT+Command, here’s an example session

And the result on mobile phone is:

Now, save it before you lost it

see this URL http://www.vallejo.cc/proyectos/envio%20sms%20english.htm