Exchanging non ASCII bytes by socket tcp

Question

Hello:
I'm trying to exchange characters between 0-255 of ascii characters table. I'm using the CharToByteConverter and ByteToCharConverter classes on my client/server programs, but I can't get it.
The client/server programs use socket tcp, but I'm not sure the data structures that I must to use in order to send bytes with these characteristics (0-255 ascii characters)
For example I need to send the next array to server program:
char[] car = new char[15];
car[0] = (char)129;
car[1] = (char)12;
car[2] = (char)201;
car[3] = (char)1;
car[4] = (char)48;
car[5] = (char)48;
car[6] = (char)1;
car[7] = (char)1;
car[8] = (char)95;
car[9] = (char)4;
car[10] = (char)17;
car[11] = (char)3;
car[12] = (char)22;
car[13] = (char)38;
car[14] = (char)53;
Note: In UDP protocol (socket UDP) the interchange data and the conversions work correctly.
Any comment will be appreciated, regads,
Ulises

Answer 1

You are right. The modem is a device that works (send
and recive) with tcp/ip or UDP/IP protocol (is a
modem GPRS). So, I can simulate him with a java
program sending data by socket tcp/ip. In this case
is the same.
The format message is a fact. I can't to choose it.Then that is the message that you are dealing with.
Presumably this is because you are only writing the client or server and not both.
>
My problem is that, for example, I'm waiting (my java
program with server socket tcp/ip actually) for a
byte 129 how first byte, but instead of it, I receive
a byte 63.
Then one of the following is true.
- You are using a class that you should not be, like DataInputStream or String.
- Your understanding of the message protocol is incorrect (perhaps because the spec is wrong.)
- Or the message that is being sent is wrong but presumably there is nothing that you can do about that.
Sockets send and receive bytes. They don't send and receive characters.
Now it could be that the data being sent is indeed characters but that has nothing to do with the socket. It doesn't transform them, map them, nor touch them in any way.
In addition, depending of the data structure used
(char [] or byte []) how buffer, I lose some bytes.Then either you are doing something wrong (like using the buffer size rather than the read size) or the message protocol is very ill defined. If the second then you will have to develope a fuzzy algorithm to guess at the correct behavior.