Possible exit/error codes of fprwin and fprinter
10: Invalid number of arguments!
12: Invalid ECR serial number!

20: The address/COM port not found! Invalid number?
22: The address/COM port can not initialize!
23: Reply timeout!

30: File not found!
31: Invalid file format!
32: Error in file line: XXX


40: Wrong CRC!
41: Invalid data received!
42: Received NACK (Negative ACK)

51: Internal error/exception during operation
53: Can't send data
54: Error during storing receipt information

Possible error codes received from the ECR:
Line Error 1 - Timeout. ACK not received
Line Error 2 - Negative ACK
Line Error 3 - Other acknowledgment
Line Error 5 - Timeout. No message received
Line Error 6 - Wrong data format
Line Error 7 - Unexpected command

