Meaning of AXC File

[kdcanada]

Hi,

I had Submited my Docs with IELTS,originals on June 7th and
I got email from buffalo visa office that application is recieved at RPC and has given the AXC file number on Nov.2, 2010.
I want to the meaning of AXC File ? Can any one tell me what would be the next step?

Thanks.