[ACELL03] Examples cannot be in headless mode without Serial

[aliphys]

The Serial monitor, together with the .setDebugStream(Serial) option provided in the Arduino_Cellular library, provides additional information on the sketch as it is executed. This can be useful for understanding/debugging the sketch by users without relying on an external JTAG interface.

Given that the Arduino_Cellular library is designed to be used with the Portenta C33/H7 (See #18) as a standalone device, the examples should also be usable in headless mode (with the while (!Serial); line commented). To this end, LED indicators (e.g. digitalWrite(LRED, HIGH)) should be used on the following sketches.

• DeleteSMS
• GetLocation
• GetTime
• HTTPClient
• HTTPSClient
• ModemTerminal
• ReceiveSMS
• SendSMS

[sebromero]

I'd argue that the examples are meant to be used in combination with Serial to understand clearly what's happening in the code. Removing the need for Serial in a production sketch can be left as an exercise to the user.