I received a few informal phone calls from different embassies/departments who were interested. The calls were conversational, about 15-20 minutes just chatting about my interests, background, and questions. The interviewers were very kind and open to talking about the position as well. Only thing to note is that you don’t get notice in advance of which departments will be calling you or when, so you don’t know who to be looking for on caller ID- make sure to pick up the phone in case!