Dear Sanjay,
Your query seems not clear to people like me perhaps because of its construction.
First, in the case of resignation, only the resignee has to give notice or pay the notice salary in lieu thereof when he is unable to serve the notice period either in full or in part. In case of resignation, the question of payment of notice salary by the employer would arise only if the employer hastens to relieve the employee forthwith or in the middle of the notice period when he is willing to serve the entire notice period as per the terms of the contract of employment..
Secondly, in any case, the completion of 240 days of service in the organization is not at all relevant to resignation.