I cannot imagine a scenario where this will work as you wish it did (always happy to be proven wrong though). Even if the call transfer routes through Intrado and maintained the original caller’s ANI (which CER is not designed to support, although I could probably think of away around that part), it’s exceedingly unlikely that Intrado’s ALI database would have a record for that ANI; the only way it would is if the original caller also used Intrado. Each carrier and national emergency provider maintains their own ALI database. When a call is connected through to the appropriate PSAP - which can only happen if Intrado knows the service address - there is a header that tells the PSAP which ALI database to query. Even if Intrado offered a way to signal this to them (they don’t AFAIK) you have no way to know the originating carrier.
The closest option I can think of is intentionally not have a location set for these users - which would potentially create legal exposure for you, especially if you made this a formal process - and rely on the nurse telling the Intrado relay center operator the caller’s service address manually. That won’t be free though.
Every healthcare customer I have ever worked with has a “if this is a medical emergency hang up and dial 911” prompt at the beginning of their welcome greeting. I don’t know the specifics of your deployment & use case but I’m frankly stunned that your lawyers are ok with employees acting as a proxy between caller and the PSAP.
Have you posed this question to Intrado directly? If yes, what did they say?
