C# send text msg/sms via USB-HSDPA Modem -> unsupported message type

1
votes

I am trying to create a text msg/sms gateway using a USB-HSDPA Modem from Huawei (E122-1). I have done this with an older Modem some time ago. After some troubles installing the driver and receiving the correct comPort of the new device I have finally established to communicate with the device.

comPort Check and PIN-Check are already done. Now I'm switching to textmode (CMGF) and write the message (CMGS):

comPort.Write("AT+CMGF=1\r\n");
Thread.Sleep(1000);
comPort.Write("AT+CMGS=\"" + "some tel no" + "\"" + Environment.NewLine);
comPort.Write("text content" + (char)26 + Environment.NewLine);
Thread.Sleep(2000);
response = comPort.ReadExisting();

everything works fine, i get proper responses and everything.

BUT, here is the problem: the sent text message can't be read on all mobile phones/smart phones:
- my old Nokia 6300 says 'unsupported message type'.
- HTC Desire shows an empty message.
- Samsung Galaxy S2 'content is not supported'.
- Samsung Galaxy S shows the message just fine.

Now here is the weird thing, if i use the application which comes with the modem (t-mobile austria internet manager) to send a text message, all of the listed devices can display it correctly.

am I missing something with the encoding or some kind of a header? (which the 't-mobile internet manager' apparently is using for correct displaying of the text message at the receiver side)

any suggestions or ideas?

thanks, Sise

2
c#sms-gateway
You use Environment.NewLine in some locaions and '\r\n' in others I would start there. Are you able to snoop wach is sent using the application that comes with the modem by chance? – Security Hound
lol that's correct, some of the code is copied from a coworker and i didn't really bother about the syntax. afaik the return/new line is for the serial communication only, just as pressing enter in a shell? currently i'm looking for the right tool to sniff the serial communication of the application which comes with the modem but didn't have luck to find a proper one so far. as soon as i get some logged data from there i will post it! – Sise

2 Answers

0
votes

somehow, the receiver devices are expecting PDU format and not ascii. something like: http://www.dreamfabric.com/sms/

but the receiver device i'm requiring this method for is a gps-tracking box and it does understand ascii, so pdu is not required and the application is working fine.

thanks anyways! :)

0
votes

Try to send in text mode: https://www.diafaan.com/sms-tutorials/gsm-modem-tutorial/at-cmgf/

AT+CMGF= 1 = Text Mode