User:Cstrathmeyer/CT Connect

What It Is
CT Connect is a software product that allows computer applications to monitor and control telephone calls. This monitoring and control is called computer-telephone integration, or CTI. CT Connect implements CTI by providing (1) server software that supports the CTI link protocols used by a range of telephone systems, and (2) client software that provides an application programming interface (API) for telephony functions.

The Beginning: Digital Equipment Corporation and CIT
CT Connect had its beginnings in the mid-1980s at Digital Equipment Corporation. During the 1980s, telephony was evolving from analog to digital technologies. The international telecommunications standards body CCITT (now the ITU) published specifications for the Integrated Services Digital Network (ISDN) and these were gradually adopted by telecommunications equipment manufacturers and network operators. The ISDN specifications provided digital interfaces between a subscriber and the network that could simultaneously support multiple telephone calls and packet data transmission.

During this time period, Digital Equipment was a leader in computer networking with its network-oriented hardware products and DECnet software. A team at Digital Equipment studied the ISDN specifications and noted that while the specifications permitted simultaneous transmission of voice calls and data there was no capability to coordinate a voice call with related data. The Digital Equipment team named this capability computer integrated telephony (or CIT) and began to evangelize the concept among vendors and customers.

(See “Voice/Data Integration: An Applications Perspective”, in IEEE Communications Magazine, Volume 25, No. 12, December 1987, pp. 30-35 and “Voice In Computing: An Overview of Available Technologies”, in IEEE Computer Magazine, Volume 23, No. 8, August 1990, pp 10-15 for early expositions of the CTI concept.)

Computer integrated telephony, as envisioned by Digital Equipment, required the cooperation of the telecommunications equipment manufacturers. The manufacturers' telephone switching systems had to report telephone call information to adjacent computer systems before any CIT functions could be implemented in a computer application. Digital Equipment found two Canadian private branch exchange (PBX) manufacturers that were interested in the idea: Northern Telecom (now Nortel) and Mitel, which at that time was controlled by British Telecom.

The team from Digital Equipment worked with both companies – one in Canada and one in the United Kingdom – to implement suitable data links so that the telephony and computer systems could be integrated. Both efforts were successful, and working CIT systems using PBXs from both companies were shown at the quadrennial CCITT exhibition in Geneva in the fall of 1987. Digital Equipment released its first CIT software products, operating with the Mitel SX-20 PBX and the Northern Telecom SL-1 PBX, the following year.

The Need for Standards
Between 1988 and 1992, the Digital Equipment team approached more telecommunications equipment manufacturers (including Siemens ROLM and the former incarnation of AT&T, whose Definity PBX product line is now owned by Avaya) and implemented the additional protocols needed to interoperate with their telephone systems. However, it quickly became clear that the number of proprietary protocols was proliferating and would soon get out of hand. Even worse, call models differed between telephone systems, making it difficult to write CTI-enabled application software. The need for a standardized cross-vendor CTI call model and supporting protocol was becoming clear.

Digital Equipment took the initiative to assemble a group of computer and telecommunications equipment vendors interested in this problem. The group approached the European Computer Manufacturers’ Association (now simply known as ECMA) with a proposal to undertake this standardization. The proposal was accepted and Robert Roden, an architect from the Digital Equipment technical team, was chosen as convenor (chairperson). Phase I (the first edition) of the resulting standard, Computer-supported Telecommunications Applications (CSTA), was released in 1992 with significant direction from the Digital Equipment team and contributions from many other delegates. The CSTA standard has since progressed through several editions, incorporating technologies such as voice response and XML. Each Phase of the standard includes both a call model as well as a recommended set of communication protocols.

See "A historical perspective of CSTA", in IEEE Communications Magazine, Volume 34, Issue 4, April 1996 for more information about the early work on CTI standards.

CTI Moves To Desktop Computers
The initial CIT products from Digital Equipment supported only VAX computers running the VMS operating system both as the server providing the telephone system interconnection and as application clients. Support for Digital's ULTRIX operating system was later added. But during the early 1990s, personal desktop computers became more pervasive in corporate computing environments. Digital Equipment responded to this trend by releasing Pathworks, a networking suite that allowed IBM-compatible PCs and Apple Macintosh computers to participate in a DECnet network. The Digital Equipment CIT team built on this platform and released a PC-based version of the CIT client that supported applications written for the Microsoft Windows operating system. The Windows desktop environment offered easier integration between business applications and telephone functions via the Microsoft Dynamic Data Exchange (DDE) mechanism, since many off-the-shelf PC applications and development platforms supported the DDE interface.

Dialogic Acquires Digital's Technology
In 1995, Digital Equipment sold the CIT product line to Dialogic Corporation, which was then the leader in server-scale telephone interfaces for the PC form factor. Digital's CIT management staff and most of the development team moved to Dialogic with the sale, forming a new 'CT Division' within Dialogic and maintaining the product’s momentum. Within only a few weeks, the team had extended the product from its original proprietary Digital Equipment hardware and software platform to industry standard client and server platforms based on personal computer hardware architectures and Microsoft Windows operating systems. The resulting product, rechristened CT-Connect, was released by Dialogic in August, 1995. (The hyphen was dropped from the name in later releases.)

CTI Becomes Popular
The 1990s saw more widespread adoption of CTI technology. Many more telephone switch manufacturers implemented CTI links for their products; some of these were proprietary protocols, and some were implementations of the ECMA CSTA standard. The CT Connect team added many of these to the list of supported products from more than a dozen switch manufacturers.

Computer-telephone APIs also proliferated. Microsoft introduced TAPI, Novell introduced TSAPI, Sun Microsystems introduced JTAPI, and a group of vendors formed the Versit Consortium to better integrate the existing protocol standards and APIs. The CT Connect team added most of these as supported client APIs.

The team also added more operating systems to the CT Connect supported list, including Unix-based operating systems from SCO and Sun.

Broad support for telephone switch link protocols, client APIs and operating systems made CT Connect an attractive platform for application development, and the team forged several significant OEM arrangements and alliances during this period.

Dialogic Acquired by Intel
In 1999, Intel acquired Dialogic and all of its hardware and software product lines including CT Connect. As with the transition from Digital Equipment to Dialogic, most of the CT Connect business and technical team remained after the acquisition and the product momentum continued. CT Connect was renamed Intel NetMerge Call Processing Software to conform to Intel product naming conventions but remained the same product under the skin.

CTI Meets VoIP
The new millenium saw the rising popularity of Voice over Internet Protocol (VoIP) telephony. The CT Connect team studied this new technology and quickly realized that CTI would be as important with VoIP as it had with traditional telephony. The team’s research and development efforts led to important [patents] in the application of CTI to VoIP, and the CT Connect product was enhanced to support application control of VoIP voice calls.

CT Connect Acquired By Envox Worldwide
Intel sold the product line to Envox Worldwide in 2005. As before, much of the technical team continued with the product during the transition. Envox restored the product name to CT Connect and offers the product for sale worldwide both directly and through distribution partners.