You are welcome. I just had to understand what you wanted to do and what the protocol said.

Be sure to look at my related post for the full RussSound array which automatically adds the F1 inversion code when needed and adjusts the data byte to its compliment form.

Put the array at the activity level so it can be referenced from the pages or wherever and only have to be defined and populated once.

If 0xF1 is required for values > 0x7F, then Barry's function with a lookup table is the better approach.

Lyndel

Barry,

I just read your post and I will use the full array. It is true that I was wondering how to handle the inversion code.

As far as Russound protocol is concerned, the array will also need to be used for the checksum control as the number of bytes is the string is taken into account in its calculation.

Thanks again.

You can use the array technique any place you need to enter a binary number in the range of 0-255 into the RussSoundProtocol. You could even use it for constants instead of "\xnn" by writing chr[nn] where nn is a number 0-255. remembering that for all values over 127 the inversion will take place so do not use it for the control characters 0xF0 and 0xF7 if they are really desired. There should be no need to explicitly use the inversion control (0xF1) as that is automatically handled.

As a further tip for clarity you might want to define some constants such as:
SOMbyte="\xF0"; EOMbyte="\xF7"; NULbyte='\x00";. . . as needed fo commonly used constants.
You can then build messages as
msg= SOMbyte+chr[i]+chr[j]+NULbyte+. . .
msg+=chr[checksum(msg)]+EOMbyte

In the above msg is a string variable, i and j are integers in the range 0-255, and checksum is a function that computes and resurns the 7 bit checksum as an integer.

It makes it a lot easier to read and understand. The checksum function would look something like this:

function checksum(a)
{var i; var b=a.length; for(i=0; i < a.length; i++;) { b+=a[i]-0;}; b+=127; return b; }

i'm trying to send a data string, where the last byte contain the luminosity parameter value:

sock.onConnect = function()
{
value=parseInt(text.label); //for example value = 31
result="\\x"+value.toString(16);
status.label = result; // it displays \x1f

sock.write("\x00\x00\x00\x00\x00\x05\x00\x10\x00\x05\x00\x01\x02\x00"+ result);

I want to have string:
sock.write("\x00\x00\x00\x00\x00\x05\x00\x10\x00\x05\x00\x01\x02\x00\x1f");


The result differs, it assigns 120 instead of 31.

How can i attach my result parameter to a data string?

If I unerstand you correctly, What you really want is the string in memory to end in a byte that has the decimal value of 31. Lets call everything up to that point FrontOfString which is of type string.

Desired string=FrontOfString+string.fromCharCode(31).

In your specific case :

sock.write("\x00\x00\x00\x00\x00\x05\x00\x10\x00\x05\x00\x01\x02\x00"+string.fromCharCode(31));

or

sock.write(string.fromCharCode(0,0,0,0,0,5,0,16,0,5,0,1,2,0,31))

The last technique being much easier IMHO

That helped me to minimize my code! Before the solution that you proposed, i used the switch case operator, with 100 case events :

...
if string == "5" write("...\x05")
...

)))

Do not take this the wrong way. I strongly suggest you buy Flannigan's book and go through it a couple of times. There are whole sections you can skip (e.g. web page construction). By doing this you will acqaint yourself with the various commands and methods available, which you can always look up later. That is what I did. If I need to do something then I use the book as a reference.

The golden rule in code writing is that if what you are doing is simple and takes a lot of code, then there is another better way to do it.

Glad to see you have not given up on postscript!

From Flanagan, Chapters 1-11 and the Javascript Core Reference in back should be all you need.