As others have stated, I do recommend having an e911 service. However, like many people today who have their cell phones on 24/7--and in most places, your cell phone has 911 service with a pretty accurate GPS location (maybe not down to the feet...but usually to the span of a house), some have obtained the local 10 digit number of their 911 dispatcher (it's the actual number that dialing 911 will route to) and have programmed it into their OBi device.
The advantage of programming the local emergency number to the OBi device is that the caller using the OBi phone will only have to dial the digits "911" to get to their local emergency dispatcher. The disadvantage is that the caller will have to tell the dispatcher their house address because it will not show up on the dispatcher's system.
If you want to do something like this, while not the best method, let me know and I will provide the configuration for the OBi200 device.