I am trying integrating a Panasonic PBX model TDA200 with cisco 2811 router.
Intial I was not getting any dial tone then PBX engg made some configurtion changes on the PBX's E&M card Then I started getting dial tone but calls were not getting matured.
Then I interchanged the tip and ring pair the calls started going through.
After only one test call I ended up with the same no dial tone problem, there was no changes made either on the router or PBX
what could be problem.