On 1/23/20 12:10 PM, Zilk, David wrote:
1)When several lines at a site don?t have DIDs, and uses a common site phone number for their CLID.? How do you provide different location information for them.
Most folks I've talked to have been urging customers to get more DIDs for years rather than continuing to hide tons of desks behind a single inbound number with extension dialing. This works well for your typical office and, while not necessarily cheap, comes with obvious additional benefits. For situations where this is either impractical due to cost or silly due to the fact that nobody's going to call those phones directly anyway (e.g. courtesy phones in a warehouse or shopping center), the approach I've heard of is to either have the phone itself add a SIP header or translate from SIP registration identity to location at the SIP proxy and add a similar header defining such a "dispatchable location" which is then passed on to the PSAP. My understanding is that such headers are vendor/operator specific. The latter complicates callback options which I gather is also an issue (I'm not a PSTN regulatory expert by any means, I mostly stick to slinging IP datagrams around). Approach I've heard of is to reserve a few DIDs for E911 callback and re-route them on the fly as outbound 911 calls are placed by putting that in the CLID field. IDK if that's kosher or not.
2) When there are shared lines on devices in different locations at a site using the same DID. How do you distinguish the correct location of an emergency call made from one of them.
The above approach works here, too.
3) When the caller uses a softphone that doesn?t have a fixed location.
This one's complicated. If you control the softphone and it's on a mobile device, you can have it provide you with the device's notion of location, which is often quite accurate especially if GPS is usable, and put that in the aforementioned headers. If you don't control the softphone, or it's on a PC, you're pretty much sunk. You may not be able to even offer service in such situations without taking additional steps. I'm not sure what these new regs have to say about that. In the past, it was pretty well understood at least my reasonably technical folks that you basically had no E911 in these situations. The approach my A-Z terminator takes if you don't have E911 data configured for a DID may be viable. They run their own 911 dispatching service that you get routed to who asks the caller for their location and then routes it, along with the appropriate manually-collected metadata, to the appropriate PSAP. Obviously they charge (handsomely) for this service.