1. The distance between "Laser transmitter circuit" and "CPU serial Port" is about 10 meters. If we use a simple wire the output signal of CPU serial Port will be distorted... it will not reach to Laser transmitter circuit in the same shape as it was transmitted.
How can i fix this problem.
2. Same problem in receiver side..
Some may say that decrease the speed of transmittion but i don't want to decrease..
10 meters isn't a problem for rs232 ... but as you say, using a simple wire, that may be your problem.
use category 5 cable (cheap and easy to come by), you should have no problems.
or better yet, see if you can find some old shielded serial cable (check with factories, banks or grocery stores) ... they should have piles of it crammed in some room with their old serial terminals after upgrading to ethernet or wireless.
$69 for a red laser is way too expensive, knowing that I could get a GREEN one for @ $50, that goes even farther. Check this site out: www.amazing1.com