Why Order of callstate is not constant under event 'OnCallStateChanged' When make consultation call to number which is busy/connected

[bhushan.bhadane1]

In our application, we have integrated Cisco switch and for telephony call control have implemented atapi api.

I'm not sure why sequence of callstate is not constant under event 'OnCallStateChanged' When make consultation call to number which is in busy/connected state.

Steps of  issue

A calls to B and B answer the call .  A and B are in connected state

C calls to D and D answer the call . C and D are in connected state

Now since A and B are in connected state and if C or D dials A then event 'OnCallStateChanged' should raise for following call states

1.Dialtone

2.OnHold

3.Dialing

4.Proceeding

5.Disconnected

If call state invoke in above order then C or D get ConsultationBusy which is correct however some of time event raise for callstates in below order and due to which C or D get ConsultationDialling instead of ConsultationBusy

1.Dialtone

2.OnHold

3.Dialing

4.Disconnected

5.Proceeding

Is it CUCM configuration issue or weird behavior of Cisco switch?

[denes.istvan]

I have seen similar state inconsistencies with monitored incoming calls, sometimes I get Offering state followed by Accepted, other times I get Accepted and then Offering. As far as I know it is not a CUCM configuration issues, it is simply how TAPI works.