.toString(radix) ?

Hello Markus,
a Happy new Year.

i've found that in the forum and it do the job as i expect.

console.log("hex:",d.charCodeAt().toString(16));

the module send some char and the last one is the SUM of the transmitted string.
i wrote something like that (i did not test it on the espruino)

let sum=0;
let buf = new Uint8Array();

function checkAnswer(buff) {
  console.log(buff.toString(16));
 switch (buff[1]) {
   case 0x01: // status
     console.log("status:",buff[3]);
     break;
   case 0x0C: //total audios
     console.log("total audios:",buff[3],buff[4]);
     break;
   case 0x0D: //current audio
     console.log("current audio:",buff[3],buff[4]);
     break;
   default:
     break;
  }
  // reset first buffer
  buf = new Uint8Array();
}

s.setup(9600,{rx:B6, tx:B5});
  s.on('data', function(d) {
    console.log("hex",d.charCodeAt().toString(16).toUpperCase());
    let nd = d.charCodeAt();
    buf.push(nd);
    sum+= nd;
    if (sum == nd && buf.length >1) {
      // fin de la transmission
      buf.pop(); // efface le sum du buffer
      sum = 0;
      checkAnswer(buf);
    }
  });

regards