posted by steve | Category: Current Projects |

Asterisk 1.6 will include a new option for distinctive ring called dringNrange, like dring1range, dring2range, dring3range. These ranges specify how much variance is acceptable in the cadence of a received distinctive ring.

Background: The local telco seems to send distinctive ring cadence in an inconsistent manner. On one call the cadence might be 175,100,0 and on the next the cadence is 201,102,0 for the same dring context. Therefore, I added and submitted patch to add a range in order to account for the variance.

In zapata.conf, you might have this:

[channels]
;incoming from pstn
;your normal other stuff goes here.
;here's a distinctive ring example
usedistinctiveringdetection=yes
dring1range=50
dring2range=35
dring1=205,97,0
dring1context=line1-incoming
dring2=384,324,0
dring2context=line2-incoming
context=default
; use fxs signalling on the fxo ports
signalling=fxs_ks
channel => 3


Now for distinctive ring 1 with a cadence of 205,97,0 anything +/- 50 will be accepted. It’s a fudge factor, I agree, but there’s simply no other way to solve the problem short of getting the telco to be consistent.

In addition to the dring range, you can also specify a -1 for one or more of the cadence values in order to indicate that you don’t care about that value. For example, I’ve found that only the first value out of the three in a given range is important. There’s enough difference in that first digit to indicate which number was being called. Therefore, instead of:

dring1=205,97,0


I could do this:

dring1=205,-1,-1


Asterisk would then ignore those last two values, treating a -1 as an indication to ignore the value.

The new dring1range, or dringNrange as it is, will be available in Asterisk 1.6 but is available now in the SVN trunk, which I’ve been using for months without issue.