I have almost working this communication.
Comercial optical probes like this are expensive:
Optical probe
So I build a optical probe based on this schematic
Communication protocol tested on my meter:
Baudrate: 300 bps, 7 bits, parity even, 1 stop bit
Send: /?!<CR><LF> (wake-up and sign-on)
Receive: /XXX5YYYYY<CR><LF> (XXX is the manufacturer ID; YYYYY is the meter ID; 5 is the new baudrate = 9600 bps)
Send: <ACK>050<CR><LF> (send ack; reading mode)
Baudrate: 9600 bps, 7 bits, parity even, 1 stop bit
Received: C.1(201236731.0(01:39 25-08-18)
1.8.1(0004398506*Wh)
1.8.2(0000000000*Wh)
1.8.3(0008198809*Wh)
1.8.4(0000000000*Wh)
1.8.5(0000000000*Wh)
1.8(0012597315*Wh)
2.8(0000000000*Wh)
!
D
Now I only have to parse the values of tarif 1 (1.8.1), tarif 3 (1.8.3), and total (1.8)