When I encode/decode SMS PDU (GSM 7 Bit) user data, do I need prepend the UDH first?

Question

While I can successfully encode and decode the user data part of an SMS message when a UDH is not present, I\'m having trouble doing so when a UDH is

Answer 1

In your case Data is D06536FB0DBABFE56C32

Get first char is D0 => h (in first 7 bit, the 8th bit not use)

The rest is 6536FB0DBABFE56C32

In bin

(01100101)0011011011111011000011011011101010111111111001010110110000110010

Shift right to left. => each right 7 bit is a char!

001100100110110011100101101111111011101000001101111 1101100 110110(0 1100101)

I shift 7 to left. you can get string from above. but i do for easy show :D

(1100101)(1101100)(1101100)(1101111)(0100000)(1110111)(1101111)(1110010)(1101100)(1100100)00

And the string is "ello world"

combine with first char you get "hello world"