EchoHam does not differentiate between repeaters, links and stations.
The communication is established to the partner IP address and at that level EchoHam is not even aware of what type of station it is.
If the other station is a mobile device (e.g. iPhone, Samsung, etc) you can not establish communication due to limitations in mobile phone networks which put these devices on a private IP address. However, that is not a limitation of EchoHam but of the network infrastructure.
If you can establish a connection to the echolink test server and your transmission is echoed back to you then you can be confident that your end is working OK.