It is very common that deductor get certificate for lower deduction of TDS from the deductee. On the basis of such certificate, lower TDS is deducted and while filing TDS return, deductor mention the certificate number in return however demand of short deduction arises due to wrong quoting of 197 certificate number.
It happens because when the deductor accepts from deductee a manually issued lower deduction certificate by assessing officer & quotes the same in TDS statements. To resolve the issue CPC(TDS) has provided the facility of validating the 197 certificate to the deductors and that if the 197 certificate is not valid as per TRACES validation, the deductor should always insist upon an ITD system generated certificate having a unique 10 digit alpha numeric number. The entire procedure for this is explained in the advisory letter issued by CBDT.