India finds itself in a unique situation (hopefully). It has several 
telephone line providers, and they are not all using the same CID 
signalling; and the CID signalling is not like other countries. 

In order to help those in India quickly find to the CID signalling
system that their carrier uses (or range of them), and get the
configs right with a minimal amount of experimentation, this file
is provided. Not all carriers are covered, and not all mentioned
below are complete. Those with updates to this table should post
the new information on bug 6683 of the asterisk bug tracker.


---------------------------------------------------------
Provider: Bharti (is this BSNL?)
Config: cidstart=polarity_in
        cidsignalling=dtmf
Results: ? (this should work), but needs to be tested?
tested by:
--------------------------------------------------------

Provider: VSNL
Config:

Results: ?
tested by:
--------------------------------------------------------

Provider: BSNL
Config: cid_start=ring
         cid_signalling=dtmf

Results: ?
tested by: (abhi)
--------------------------------------------------------

Provider: MTNL, old BSNL
Config: cidsignalling = v23
        cidstart=ring

Results: works
tested by: (enterux)
--------------------------------------------------------

Provider: MTNL (Delhi)
Config: cidsignalling = v23
        cidstart = ring

cidsignalling = dtmf
cidstart = polarity_IN

cidsignalling = dtmf
cidstart = polarity

Results: fails
tested by: brealer
--------------------------------------------------------

Provider: TATA
Config: cidsignalling = dtmf
        cidstart=polarity_IN

Results: works
tested by: brealer
---------------------------------------------------------

Asterisk still doesn't work with some of the CID scenarios in India.
If you are in India, and not able to make CID work with any of the
permutations of cidsignalling and cidstart, it could be that this
particular situation is not covered by Asterisk. A good course of 
action would be to get in touch with the provider, and find out from
them exactly how their CID signalling works. Describe this to us,
and perhaps someone will be able to extend the code to cover their
signalling.