UPC bar code

[Rasathi]

There is a UPC bar code in the appointment letter for the visitor VISA. What is the purpose of it?

Thanks in advance
Rasathi

[ronline]

For which consulate is this?

[Rasathi]

I have booked the appointment in Chennai for visitor VISA to come to US.
I got the appointment which has the UPC bar code and details of the persons passport at the bottom. So what is the use of the UPC bar code?

[ronline]

You just have to take the appt letter with you - its a tracking barcode.