I'm trying to run ussd code via gsm modem to get sim balance. I'm using GsmComm library, ASP.NET Web Form, C#. Below is my code : public string SendUssdRequest2(string request) { comm = Connec...

Here is my code: According to this page the CreateConcatTextMessage method returns an array with type SmsSubmitPdu[] but, when I try to send it with SendMessages I get a MessageServiceError 500. W...