Problem converting HEX string to ASCII

Samuele Rossi

Hi all, i have this string in HEX: 00024944554E49563130434800A0 and need to convert in ASCII.

I have tried to use the following solution, but the encoding of the last parte of the string is incorrect "00A0" after the conversion in ASCII (and converted again to be sure of the date transmitted) became "003F", probably is an Encode problem, but i dont know how and where use it with success.

public static string HextoAscii(string HexString)

{

string asciiString = "";

for (int i = 0; i < HexString.Length; i += 2)

{

if (HexString.Length >= i + 2)

{

String hs = HexString.Substring(i, 2);

asciiString = asciiString + System.Convert.ToChar(System.Convert.ToUInt32(HexString.Substring(i, 2), 16)).ToString();

}

return asciiString;

}

Thank you very much for your help :)

4 Replies

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Samuele Rossi12y ago
I'm sorry, my fault, i did a mistake 00A0 is 160 (not on first page of ASCII chars). Is not a checksum.
Vulpes12y ago
Well, -2 in two's complement notation is FFFE hex so it's difficult to see how 00A0 could be interpreted in this way.

Could it perhaps be a checksum for the rest of the string?
Samuele Rossi12y ago
The conversion IDUNIV10CH is right. 00A0 should be a -2 value in MODBUS standard.

Anyway i did a first conversion from ASCII to Hex using Encode.Unicode and worked good (i got all the values expected). One of the value was this 00A0 that i need to gove back as Echo of the file.
The problem that i have is to convert it back.
Vulpes12y ago
How does this string arise?

I don't recognize 00 02 as a byte order mark so I wondered whether it was coming from a serial port device rather than a file?

02 (or STX) means 'start of text' in some old transmission protocols.

Assuming it was encoded in ASCII in the first place, the only printable characters are:

IDUNIV10CH

which might make some sense.

There are, of course, many single byte 'extended ASCII' encodings where A0 might mean something. For example in Windows 1252 it means 'non-breaking space'.