add different ringing tones for FXS port, so customer can hear which number is calling on analog phones or bell. It is the same feature as Distinctive Ringtone for SIP phones.
We have done it this way in extensions_custom.conf file:
exten = 80,1,Wait(1)
exten = 80,n,Dial(DAHDI/4r2,60,iTtKkXx) ; ' r2' = ring pattern 2 for bell '4' = FXS port 4
exten = 80,n,Hangup()
include = bell ; add to the list,so the pbx knows number 80