Online PDU Decoder

The SMS specification has defined two modes in which a GSM/GPRS modem or mobile phone can operate. They are called SMS text mode and SMS PDU mode. (PDU stands for Protocol Data Unit.) The mode that a GSM/GPRS modem or mobile phone is operating in determines the syntax of some SMS AT commands and the format of the responses returned after execution.


Online SMS PDU decoder support SMS-SUBMIT,SMS-DELIVER and SMS-STATUS-REPORT.

Decode PDU by https://www.smsdeliverer.com
Message 1/1
Main information
To:smsdeliverer.com
Message:Hi, SMSDeliverer.com!
Additional information
PDU TYPE:SMS-SUBMIT
SMSC Address:86123456
Data coding scheme:SMS Default Alphabet
Message class:Class 0
Reference No.:0
Source port:-
Destination port:-
Physical SMS length:0/1
Val. format:Relative
Validity:24 hour(s)
Original Encoded PDU fields
SMSC:86123456
PDU Header:11
  TP-MTI:01
  TP-RD:0
  TP-VPF:00
  TP-SRR:0
  TP-UDHI:0
  TP-RP:0
TP-MR:00
TP-DA:smsdeliverer.com
TP-PID:00
TP-DCS:00
TP-VP:10
TP-UDL:15
TP-UDH:
TP-UD:C8340B346D4E896576DA5E9697E5AEF1BB1D02

Detailed SMS-DELIVER PDU Structure

The SMS-DELIVER (Mobile Terminated) PDU is the format used for messages arriving at the mobile station. It contains the sender's info and the network arrival timestamp.

Field Name Size Technical Detail & Encoding
SCA Length 1 Octet SMSC Address Length: Indicates the total length of the SMSC info (Type + Number).
SCA Type & Number Variable The phone number of the Service Center that delivered the message (BCD-encoded).
First Octet 1 Octet PDU Type: Defines TP-MTI (00 for Deliver), TP-MMS (More Messages to Send), and TP-RP (Reply Path).
TP-OA Variable Originating Address: The sender's phone number, including length, type, and BCD-swapped digits.
TP-PID 1 Octet Protocol Identifier: Identifies the higher layer protocol or specific message handling.
TP-DCS 1 Octet Data Coding Scheme: Defines the alphabet (GSM 7-bit, 8-bit, or UCS2/Unicode).
TP-SCTS 7 Octets Service Center Time Stamp: The time when the message arrived at the SMSC (BCD format).
TP-UDL 1 Octet User Data Length: Indicates the number of septets or octets in the received message.
TP-UD Variable User Data: The actual received message content (the payload).

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See also:
Online SMS PDU encoder