For some customers, their corporate HQ mandates Credit Card processing must use a Standalone Terminal disconnected from the POS UNLESS they are on P2PE-EMV/Semi-Integrated terminals.
Standalone terminals are highly undesirable as they are totally cut off from the POS and require manual entry of amounts – slower and error/theft prone.
If you are using any of the below for your credit card processing and still use a Standalone you should know you have an alternative option to standalone by using P2PE-EMV Terminals that are separate from the POS but still communicate with the POS computer to coordinate sales data like amount to charge and get back an approval code ( but never sensitive data).
World Pay (but only thru TSYS as of yet)
VANTIV (IP platform).