I have a customer with 3 sites and a number of home workers in the UK.

The customer uses Extension mobility throughout.

The customer is asking how we can correctly show a phones location when dialling 999 i.e one of the 3 offices or home location, I have looked at Emergency responder but it seems expensive so looking at alternates.

Based on where the user is I just want to amend the CLI given to a phone when it dials out so if they log in to a phone at site A use CLI 12345 if site b use CLI 54321 etc

All the E1 links are based at main site so no local break out. Any idea if this can be achieved with out CER?

Thanks