We have sites with a working ADSL connection using a Cisco 887, standard config.
A need arises to identify onsite the PSTN number the router is connected to. Taking into account that customers and engineers might not have analogue phones to simply plug in and dialout to a mobile. Is there a way to get the router to make a PSTN call or debug to show incoming calls and the phone number. Back in the days of ISDN this was easy, you could dial an ISDN line with a phone and see the debug.
If this can be achievable, it would be a handy troubleshooting way of finding your PSTN wall socket out of a sea of unmarked sockets because BT never mark them!