I've used the code here on the forum but what I can not handle is negative numbers.
There have been more that 170, 000 posts. We could not begin to guess which of those posts contain the code you are using.
I have negative numbers that I have to use in my other Arduino.
If you have negative numbers, you must not be using an unsigned type. That is not, then, the source of your problem.
Desire is to send all this in a string such as for example
*- 50 79 25, all numbers can be a digit or more and could be negative.
or maybe something like this
*x=value y=value temp=value
Either format is almost trivially simple. Using Serial.print(), the value specified is output as a string.
May I respectfully suggest that you use a closing delimiter, too. Send something like:
<-50 79 25>
This makes it much easier to determine when all the data for a packet has been received, and allows some level of checking for completeness. For example, there are two spaces in the string, so if you read '<', a number, a space, a number, a space, a number, and '>', you could be reasonably certain that there was no data loss.
If you have trouble sending or receiving and parsing the data, post your code. We'll be happy to help you get it working.
Writing it all for you, though, is not something we really want to do.