Error: No such file or directory, cannot open /dev/ttyS13

Hi

I am not sure how I can use this, but I tried, and got an error:

```
node mbusreader.js
Error:  Error: No such file or directory, cannot open /dev/ttyS13
```

How can I connect to OssBrikken?

And how are you doing with the API? I am looking forward to trying it :-)

Otto