even without a mobile phone,just with a paper wallet,it is possible
But a simple smartphone or a tablet is preferrable to verify the bitcoins has been received
I wish you can show us how to take care of the business and bitcoin payment with paper wallet alone. If someone is in charge of business like that there are certain requirements imo.
I doubt you can do this without computer, smartphone etc. (ok, you can do manage your business without it, but in that case why would you want to accept bitcoin? It is a contradiction.)