How should we control Cisco phones using 3rd party call control?

Question

Background
We are developing an enterprise application to control Cisco phones on a Cisco Unified Call Manager using 3rd party call control. We need to be able to monitor call state, get Caller ID for incoming calls, and do full call control (placing calls, answer, hangup, conf, transfer, etc). Our customers will probably be using CUCM 7.1 through 8.5.

We're developing the app using .Net - which makes development using JTAPI clumsy though possible. Maybe this is the best approach?

We have done first party call control using Cisco's TAPI interface, but it is not clear that this will work in a third party call control mode. Also, we're unsure of the stability of this API.

We don't want our customers to have to buy anything extra - ie no Unified Contact Center...

We've seen references to a CTI interface into the CUCM - ie whatever the desktop TSP connects to in order to control phones. Is this API available?

Also, we've seen references to CSTA as a mechanism to control phones on a CUCM.

The Question
What is the recommended method for 3rd party call control on a Cisco Unified Call Manager in an enterprise environment for .Net developers?

Answer 1

Your options are:

1. TAPI3 - uses TSP (that is need an installation saparatly).
2. JTAPI - that has it's own disadventages (Services in MS endpoint or servers, IIS related etc...)
3. CTIOS - you have to know the struct of each packect. pdf here
4. REST - dont know mach about this method.
5. I think there is more but i have no familiar with them.

JTAPI

Answer 2

You would use a CTI port and open it in third party mode to monitor multiple lines on a Cisco through Call Manager. We worked with Cisco to fix a but in their TAPI TSP so believe it to be a fairly reliable method. Call Manager Express also has a TAPI implementation. Most of the PBX manufacturers don't write their own TSP. They contracted it externally. Interestingly, they hired two different companies to write the TSP for Call Manager and Express! You can also use SIP and TAPI/SIP gateway software to handle any calls you expose through a SIP Trunk.

I work at ExceleTel and we use our TAPI programmers controls in some pretty heavy duty TAPI Call Center applications created in VB6, VB.NET, C#, and Delphi. So it is a time-tested solution.