IPATS Client is a calling application that allows you to make and receive calls using the SIP protocol. With a maximum of two lines, users can easily switch between incoming calls and make outgoing calls. Unfortunately, simultaneous calls with multiple people are not possible at this time.

The app features a built-in contact list, allowing users to quickly call their saved contacts. Please note that the contact list is directly linked to the phone's contact list, so users cannot add or delete contacts directly within the app.

Overall, IPATS Client is a user-friendly app that simplifies calling with its straightforward interface and SIP protocol support.