用于SIM 900的Arduino GSM数据连接

Question

我正在使用SIM 900 GSM模块，我使用此代码进行基于GSM的数据连接。但问题是我没有从我的代码中获得任何反馈。我来自孟加拉国，使用当地SIM卡提供商的SIM卡（Grameen Phone（Telenor））。它的APN是gpinternet / gpwap。但是什么是用户名＆amp;密码。如果模块可以连接，那么它将显示一些正反馈否则为负。但它没有显示任何东西我的问题在哪里？谁能帮我。

#include <GSM.h>
#define PINNUMBER "1234"

// APN data
#define GPRS_APN       "gpinternet" // replace your GPRS APN
#define GPRS_LOGIN     ""    // replace with your GPRS login
#define GPRS_PASSWORD  "" // replace with your GPRS password
// initialize the library instance
GPRS gprs;
GSM gsmAccess;     // include a 'true' parameter for debug enabled
GSMServer server(80); // port 80 (http default)
// timeout
const unsigned long __TIMEOUT__ = 10 * 100;
void setup() {
  // initialize serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }
  // connection state
  boolean notConnected = true;
  // Start GSM shield
  // If your SIM has PIN, pass it as a parameter of begin() in quotes
  while (notConnected) {
    if ((gsmAccess.begin(PINNUMBER) == GSM_READY) & (gprs.attachGPRS(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD) == GPRS_READY)) {
      notConnected = false;
    } else {
      Serial.println("Not connected");
      delay(1000);
    }
  }
  Serial.println("Connected to GPRS network");
  // start server
  server.begin();
  //Get IP.
  IPAddress LocalIP = gprs.getIPAddress();
  Serial.println("Server IP address=");
  Serial.println(LocalIP);
}
void loop() {
  // listen for incoming clients
  GSMClient client = server.available();
  if (client) {
    while (client.connected()) {
      if (client.available()) {
        Serial.println("Receiving request!");
        bool sendResponse = false;
        while (char c = client.read()) {
          if (c == '\n') {
            sendResponse = true;
          }
        }
        // if you've gotten to the end of the line (received a newline
        // character)
        if (sendResponse) {
          Serial.println("HI man");
        }
      }
    }
  }
}