Tds

But in CIRCULAR NO : 17/2014 F.No. 275/192/2014-IT(B) of Central Board of Direct Taxes it is clearly mentioned  - "3.5 Information regarding Income under any other head:
(i) Section 192(2B) enables a taxpayer to furnish particulars of income under any head other than "Salaries" ( not being a loss under any such head other than the loss under the head ― Income from house property‖) received by the taxpayer for the same financial year and of any tax deducted at source thereon. 

The employee shud give all the details of his income from sources other than salary alongwith the TDS made thereon whihc shud be disclosed in his investment declaration given to teh employer.

The employer would then calculate the total income of the employee,  calculate the taxable income and then deduct tax accordingly.