Pos Printer sending ESC/POS commands

#1

Hi, in my ionic app, iam using bluetooth serial plugin to connect to pos printer, so i can print bills. Everything is working fine, but i have problems with diacritics(instead of some czech characters it prints Chinese). I find out, that i have to send some commands to printer(its ESC/POS compatible), but i dont know how to do it. Do i have to send pure string or encode it somehow? Currently my code looks like this:

print(billToPrint){
    return new Promise((resolve,reject)=>{
      this.bluetoothSerial.list().then((data)=>{
        if(data.length==0) reject(new Error("Printer not connected"));
        let subscription=this.bluetoothSerial.connect(this.selectedPrinter.address).timeout(3000).subscribe(data=>{
          console.log("subscribed",data);
          this.bluetoothSerial.write(billToPrint).then((data)=>{
            resolve(true);
          });
          subscription.unsubscribe();
        },err=>{
          reject(new Error("cant connect to printer"));
        });
      },err=>{
        reject(new Error("error finding bluetooth connection"));
      });
    });
  }

Any ideas?