When you receive or make a call using and Infocaller Virtual Number, and your extension is configured to allow call control (which it is by default) you can control the call from the APP. You are able to put the call on hold, call another extension, alternate between caller and extension and transfer the call to the new extension. The app also allows you to send dial tones when accesing automated services.This functionality is described here. 

When your call is active you have buttons to terminate the call or to put it on hold.

Once you press <hold> you will be show the extensions of the line which received the call. You can return to the call and not transfer it by pressing on <Return to call> or you can press on an extension to call it. hile you do this, the caller will be listening to a hold tone.

When the extension you selected answers, you will be able to alternate between the caller and the extension by pressing on the recover botton of the corresponding party.  If you wish todo so, you can transfer the call to the new extension, after which your call will be terminated.  You can also terminate the call to the extension and return to the caller. Or you can end all the calls at once.