BatchDialer lets you listen to the conversation your agent is having with the lead and even barge into the call if you want to.
Once you are on your dashboard you can click on Reports which will direct you to Live page.
Once you have clicked on the Reports > Live link in the menu the below screen will appear where you will see the live Inbound and Outbound calls and once the call is connected you will be able to listen to it and also barge in.
For barging into the call you should have Agent feature enabled.
Once your VA is connected to a lead, you will be able to see the Status as ONCALL and a headset and ear icons will appear and by clicking on the headset icon you can listen to the conversation between your VA and lead.
As shown below screenshot you can click on the highlighted icon to barge into the call and participate in the conversation.
As shown in the below screenshot once you click on the barge-in icon you will see the dial-pad appear and you also have control over the connected call.