It really depends upon whom you have access of. If you have access to the Phone only, then you can't do much more. Because now a days servers/routers aren't using such simple way to track initial location of the RTP stream.
If you have access to the server and call was connect via IP only then you could do much better. You can see the Logs of your mobile to see where call came from. If the call was TDM and came from landline then you can also check logs and ask from upstream providers for the location of receiving call.
All the calls can be trace down if there is a really need for it. Higher authorities can use other meanings to solve this issue. Because they can trace the exact geographical location of that call. Or they can check the name of the person with whom that landline was registered or sim owner name and identity card number.
