Hello,I described the problem inhttp://forum.arduino.cc/index.php?topic=279021.new#new and got some answers in RECAP:I want to use ethernet shield R3 and GSM shiled R3 on MEGA 2650 an get control characters in the serial comm window when I put GSM shield on top of the ethernet shield. When I remove the GSM shield the server part works fine.Somebody answered in http://forum.arduino.cc/index.php?topic=217423.new#new page 3., that i am using the wrong ports with the MEGA but the ports I use in the sketch mentioned in the first link is Serial. I think this is on pin 0 and 1. Do I only have to change the Serial.begin.. to e.g. SoftwareSerial mySerial(10, 11); // RX, TX.And what about the connection of pin 10 to pin 2 and bended the GSM shield pin 2 ?? ps. The ethernet board has a six pin connector SPI and is on the Mega. The GSMs shiled is on top of it.