Fake Ring
This option is available starting from MOR9
This function lets set Fake Ring signal on Devices/Providers which do not send correct RING signal. This should not be used very often, because it is unprofessional.
Generate a ringing tone for the calling party, passing no audio from the called channel(s) until one answers. Without this option, Asterisk will generate ring tones automatically where it is appropriate to do so; however, "r" will force Asterisk to generate ring tones, even if it is not appropriate. For example, if you used this option to force ringing but the line was busy the user would hear "RING RIBEEP BEEP BEEP", which is potentially confusing and/or unprofessional. However, the option is necessary in a couple of places. For example, when you're dialing multiple channels, call progress information is not consistently passed back. (http://www.voip-info.org/wiki/view/Asterisk+cmd+Dial)
It can be set in Device and Provider details:
