E-911 has one really invaluable feature known as called party trunk
> and line sezure. No matter how briefly you're off-hook, once you dial
> 911 you cannot release the connection. Only the call center can
> release the connection.
> I wonder if that is even technically possible via VoIP assuming
> unrestrained cooperation of the LEC that holds the marbles, so to > speak?
Sure it's possible if you implement the feature into the hardware and software. As it is, it's likely fully not possible, although a combination of rerouting all outbound calls to the E-911 operator and immediately redialing the number (and letting it ring indefinitely, without going to voicemail) would do the trick.