Just like payment terminal solutions, mobile EMV card-present solutions can belong to one of the three kinds: fully integrated solutions, standalone solutions, and semi-integrated ones.
Every mobile solution features a card reader, connected to a mobile device, on which mobile POS system is installed.
In fully integrated solutions encrypted card readers are used. These solutions do get the merchant’s mobile POS app out of PCI scope. But if the merchant has to accept EMV cards, all the EMV path still has to be certified, as provided by the EMV regulations.
Standalone solutions involve some separate app, usually provided (and EMV-certified) by the payment gateway.
Semi-integrated solutions call for development of a special component, which performs basic payment operations, but does not allow any interaction with the EMV kernel, thus, getting the POS system out of the EMV path.
To learn more about EMV mobile solutions, check out the respective article on Paylosophy.