Right O.
I have spent the whole weekend trying to get this running smoothly.
Now I need help.
I have a SM5100B on the Sparkfun Shield.
I can get it to send ONE text SMS fine each time it restarts then it fails of ages (like 5 to 10 min), with +CME ERROR:4.
After a while it will send one message again.
I have tried two ways to send, both do the same.
What is missing?? It has got to be something like that.
PLEASE help, Im ready to chuck it in. 
Here is my code, two examples listed..
Thanks.. M
// Define messenger function
void messageCompleted() {
// This loop will echo each element of the message separately
while ( message.available() ) {
if ( message.checkString("OK") )
{
digitalWrite (ReadyLed, HIGH);
digitalWrite (BusyLed, LOW);
Serial.println("GSM Ready - OK");
}
if ( message.checkString("+CME ERROR: 4") )
{
Serial.println(string); // Echo the string
Serial.println("+CME ERROR:4 -operation not supported. ");
digitalWrite (ReadyLed, HIGH);
digitalWrite (BusyLed, HIGH);
}
if ( message.checkString("+SIND: 4") )
{
Serial.println("SIM Ready");
bootOneTime();
}
message.copyString(string,MAXSIZE);
Serial.print(string); // Echo the string
Serial.println(); // Terminate the message with a carriage return
}
}
void sendSMSpreamble() {
delay(1500);
cell.print("at+cmgs="); // comand message
cell.print(34,BYTE); // "
cell.print(PHONE); // Insert phone number
cell.println(34,BYTE); // "
Serial.println("preamble");
delay(1500);
}
void sendSMSappend() {
delay(500);
cell.println(26,BYTE); // end of message command Ctrl-z
Serial.println("append");
delay(5000);
isActive0 = 0; //Finished Sending
}
void sendErrorSMS() {
sendSMSpreamble();
Serial.print("Error: ");
// cell.print(errorMsg[error]);
// writeStatus();
sendSMSappend();
}
void StatCheckGSM() {
cell.println("atz");
delay(1000);
}
void sendTestSMS() {
SetMode();
sendSMSpreamble();
sendStatus();
sendSMSappend();
}
void sendStatus() {
cell.print("Test SMS: ");
cell.println(SMS0);
Serial.println("message");
}
void sendStatusSMS() {
sendSMSpreamble();
//writeStatus();
sendSMSappend();
}
void SetMode() {
cell.println("at+cmgf=1"); //Set message mode to Text (1)
Serial.println("setmode");
}
void bootOneTime() {
digitalWrite (ReadyLed, LOW);
digitalWrite (BusyLed, HIGH);
cell.println("at+cmgf=1"); //Set message mode to Text (1)
delay(1000);
cell.println("AT+CSQ"); // Check signal strength
Serial.println("System Ready....");
digitalWrite (ReadyLed, HIGH);
cell.println("AT+CMGD=1,4");
}
Also Have tried the following.
// Send the restore SMS
if ( SMS1 >= 1 && isActive1 == 0 ) {
Serial.print("Door-1 Restore. Now Closed after "); // Do something only if interval has elapsed and the metro is "active"
Serial.print(SMS1);
Serial.println(" times.");
Door1Metro.interval(timing);
cell.println("at+cmgf=1");
Serial.println("at+cmgf=1");
delay (100);
cell.print("at+cmgs=");
Serial.println("at+cmgs=");
cell.print(34,BYTE);
cell.print(PHONE);
Serial.println(PHONE);
cell.println(34,BYTE);
//cell.print(13,BYTE);
cell.print("Door 1 Restore. Door 1 Now secure. Door trigger was looped ");
cell.print(SMS1);
cell.print(" times.");
cell.println(26,BYTE);
cell.print("ok");
SMS1 = 0;
}
//cell.println("at+cmgf=1");
//cell.print("at+cmgs=");
//cell.print(34,BYTE);
//cell.print(PHONE);
//cell.println(34,BYTE);
//cell.print("Your Message Here");
//cell.print(SMS1); //insert counter
//cell.println(26,BYTE);