JBee:
[...]
Serial.begin(9600);
Serial.println("P1 Smart meter reading - START\n");
[...]
Do you have any suggestions ?
The IEC62056-21 standard dictates an initial rate of 300 baud [edit: sorry, should have looked better, your're trying an electrical interface, I made an optical one, 300 baud refers to the optical standard within IEC62056]. One can negiotiate a higher baud rate after initial communication but that is not needed for readout only.
Some info for interfacing with smart meters:
Type of transmission:
Asynchronous serial bit (Start – Stop) transmission according to ISO/IEC 1177:1985, half-duplex.
Transmission speed:
Initial baud rate – 300
Standard baud rates – 300, 600, 1 200, 2 400, 4 800, 9 600, 19 200.
Character format:
Character format according to ISO/IEC 1177:1985.
(1 start bit, 7 data bits, 1 parity bit, 1 stop bit).
Character code:
Character code according to ISO/IEC 646:1991, international reference version. For local use,
a national replacement code can be used.