03 02 01 0a 02 43 0b 00 1d 39 01 1a 00 01 00 07 91 55 11 18 31 28 00 0e 31 20 04 81 21 43 00 00 ff 04 d4 f2 9c 0e 

03 -
02 -
01 -
0a -
02 -
43 -
0b -
00 -
1d -
39 - TransactionID 3, SMS messages
01 - CP-DATA
1a - Length: 26
00 - MTI 0 RP-DATA (ms-> n)
01 - MR 1
00 - RP-OA
07 - RP-DA (SMSC Length)
91 - International No, Numbering Plan
55 11 18 31 28 00 - 551181138200
0e - RP-UD len (14)

TPDU (14 byte):
31 - MTI(01), VPF(2:relative), MMS(0), SRI(1), UDHI(0), RP(0)
20 - Message Reference
04 - DA length
81 - Numbering Plan, National number
21 43 - DA 1234
00 - PID
00 - DCS
ff - Validity period
04 - User Data length (04)
d4 f2 9c 0e - gsm_default 7bit encoded "Test" (4 byte)