Well there is a special way you have to set it up the first time, it needs to acquire GPS signal for 911 and emergency services then it can be moved anywhere in the house and you need to go into your att account online to register device phone numbers. You can have I believe 5 devices registered at once, possibly 6, I dont remember. It is about 10 inches tall, 8 inches deep and 4 inches wide just from a rough guesstimate. Not sure how well it would work on the road though since you need to pick up GPS signal each time you change locations. Might want to call ATT and ask first. It also works best when it is placed before the router or switch, not on them so unless you have access to the source of the network you may have spotty reception even though you have full coverage. The microcell should have priority on the network for clear calls.