Whenever I make a call from the PSTN to my internal phone I hear a ringtone and call charges start, but the ip phone is not ringing. I have also added the plar command under the voice-port but still the same issue. My phone is running on SIP. I am using cisco 2901 router and ios 15. The port is a FXS port.
Config:
voice-port 0/0/0
connection plar 105