tx wizbang
ya i have download a tonegenerater from the site wich you have mentioned..but as i have stated earlier that it generate only "ding dong" typle tone...

one more thing i want to clear that though i m an civil engineer i am also a electronics hobbiest. if you surf hamradio site ,for digital communication now a days soundcard interfaces are available and any one can purchase or can make himself olso.That is why i am using soundcard interface which is made by me..Ok i have no deep knowledge of vb in this direction i have to follow others.. I think you have done more works on this filed of ellectronics you will be the better guide in this subject..As you told that as my requirement is diffretnt rather non-practical but there is so many software available of didgital communaation vis sound siganl...

I DONT KNOW WHERE SHOULD I STOP....LOL