SMS-SUBMIT in 8bit

It is possible to use a 16 bit CSMS reference number in order to reduce the probability that two different concatenated messages are sent with identical reference numbers to a receiver. In this case, the User Data Header shall be:

• Field 1 (1 octet): Length of User Data Header (UDL), in this case 06.
• Field 2 (1 octet): Information Element Identifier (IEI), equal to 08 (Concatenated short messages, 16-bit reference number)
• Field 3 (1 octet): Length of the Information Element (IEL), excluding the IEI and the IEL; equal to 04
• Field 4 (2 octets): 0000-FFFF, CSMS reference number, must be same for all the SMS parts forming the concatenated message
• Field 5 (1 octet): 00-FF, total number of parts. The value shall remain constant for every short message which makes up the concatenated short message. If the value is zero then the receiving entity shall ignore the whole information element
• Field 6 (1 octet): 00-FF, this part's number in the sequence. The value shall start at 1 and increment for every short message which makes up the concatenated short message. If the value is zero or greater than the value in Field 5 then the receiving entity shall ignore the whole information element.

0051000C912943524295050004AA0F060804112F01014869206475646521

-SCA : 00

-PDU Type : 51 (01010001)

from right 

bit0,1: 01:SMS-SUBMIT

bit3,4 : 10 : VPF present

bit6 : UDHI present

-MR : 00

-DA : 0C91294352429505

lengrh : 0C : 12

number : [phone]

-PID : 00

-DCS : 04 ( 8 bit ) binary

-VPF : AA

-UDL : 0F : 15

-UDHI : 060804112F0101

-UD : 4869206475646521

Hex to string : put above UD 

https://codebeautify.org/hex-string-converter