It seems that in your appointment letter, there is a mention that the basic pay or gross pay has not been specified in lieu of notice pay. This suggests that the letter might not provide clear details about how your basic or gross pay is calculated when considering notice pay.
If you have any concerns or questions about your compensation structure, it would be advisable to seek clarification from your employer or the human resources department. They should be able to provide you with the necessary information and address any uncertainties you may have regarding your pay and notice period.
Communication with your employer can help ensure transparency and avoid any misunderstandings related to your compensation.