How to send SMS by GSM modem in PDU mode?
I want to send SMSs in PDU mode. I have checked the spec for my modem, and it supports PDU mode.
I have developed a PDU encoder and decoder, but now I do not know how to send data to my modem. I tried these AT commands:
AT
AT+CMGF=0
after sending these commands I sent the PDU data like this:
AT+CMGW="16079189390500410011000C918939050000000000AA02E834"
I have checked the correctness of this PDU using this online tool :
http://www.twit88.com/home/utility/sms-pdu-encode-decode
but after sending it via the AT command, the modem hangs.
Is this the right way to send SMS PDUs? I searched on Google and can not find useful information.
Answer
First of all, to send sms when modem is in pdu mode, you must send these commands: AT+CMGS=<length> <CR>, where length is (length of PDU binary string - 2) / 2. When '>' symbol appears you must send your pdu and ctrl+z character (char.ConvertFromUtf32(26)).
Here are some resources that may be useful: http://www.developershome.com/sms/ SMS Tutorial http://www.diafaan.com/sms-tutorials/gsm-modem-tutorial/online-sms-deliver-pdu-decoder/ another online pdu decoder (but your link is better in my opinion) http://www.fccps.cz/img.asp?attid=24590 AT commands guide (for wavecom, but there is no difference)
Last advice - use any telnet client to connect and test your modem and see how it responds