XSB connects to a voice room that is specified in the controller's ATIS when you join a controller's frequency. If you got to a frequency on which there is no controller (ie, 122.80), it will not join a voice room. This is why there is no voice unicom capability in XSB. FSInn (msfs) lets you join an arbitrary voice room. However, that's still not a simulation of unicom, because there is no range limitation, unless you join a 'regional' unicom voice room, ie. "Australia_12280" XSB operates with the expectation that it will receive position reports every 5 seconds. It is possible to do limited formation flying, as long as you're not doing a lot of aggressive maneuvering. Straight and level works fine. Bear in mind, XSB interpolates the position of aircraft between known points (by running 5 seconds delayed, if I understand it correctly). Hence, the animation of aircraft, frame by frame, should be quite smooth. Full disclosure: I am the founder of PilotEdge... PilotEdge has a radio system that is not 'voice room' based (it does use voice rooms on a 3rd party voice server under the covers, but that is largely irrelevant). You can tune to ANY frequency, and if your buddy tunes to the same frequency AND he is nearby, then you will hear eachother on the radio. If you're both on the ground, 10nm away, then you won't be able to hear each other. As you takeoff and climb a few hundred feet, you'll soon hear each other on the radio. Regarding position updates, PE sends data every 3 seconds for distant target or 5 times PER seconds for nearby targets. It also sends light settings (landing, strobe, position, beacon), an engine setting and flight control settings (flaps, spoilers, aileron, elevator, rudder). We'll eventually use a new OBJv8 CSL format which will allow multiplayer aircraft to have animated controls. Right now, we simply show the change in light settings (a very handy feature, I have to tell ya). We have done 5-ship formations at 500-600kts at low level on published military training routes (VR-1257 and VR-1256 in southern california, starting near SMX, heading to PMD, PSP and eventually JLI VOR if anyone is interested in trying it out). 3 of the aircraft were recorded drones, 2 of us were live. The fidelity of the playback was such that it wasn't possible to tell who was live and who was a drone. Small aside, for anyone who enjoys formation-flying, this is the network for you, even if you NEVER say a word to ATC. We have 200+ aircraft flying around 24/7 (we can record more at any time) doing everything from pattern work in GA singles, air work in light twins and singles, GA VFR cross countries, helicopter air tours around Catalina, glider flights launched off a winch (using ridge lift to stay aloft for about 30 minutes before heading back to the airport), bizjet ferry flights and, of course, a boatload of interesting military activity on military training routes and in special use airspace. I hope to ramp up the staffing from part time (3 days a week, 4 hours a day) to full time in a few weeks from now.