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

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" + "\"" +开发者_运维百科 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

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! :)

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

AT+CMGF= 1 = Text Mode