rain_send_and_wait
err = rain_send_and_wait(rain, "R", "REV");
err = rain_send_and_wait(rain, "Q 1", "QTY");
err = rain_send_and_wait(rain, "c0000", "CFG");
return rain_send_and_wait(rain, "A F 0000", "ADR");
return rain_send_and_wait(rain, cmd, "ADR");