Arduino 2560 r3 and Windows 7 Home 32bit Problem

I just want to send one character from Command line and to receive at my arduino Variable but i am receiving always -1 The Rx led blings each time i send the command from command line typing "echoe 55 >com4" void setup(){ Serial.begin(115200); } void loop(){ Serial.read(); delay(100); }

I just want to send one character from Command line and to receive at my arduino Variable but i am receiving always -1

You wouldn't, if you only read() when there was data available(). Given that pathetic little bit of code, there is no way that you know that Serial.read() always returns -1.