Computer telephony integration


Computer telephony integration, also called computer–telephone integration or CTI, is a common name for any technology that allows interactions on a telephone and a computer to be integrated or coordinated. The term is predominantly used to describe desktop-based interaction for helping users be more efficient, though it can also refer to server-based functionality such as automatic call routing.

Common functions

By application type

CTI applications tend to run on either a user's desktop, or an unattended server.
;Common desktop functions provided by CTI applications
;Common server functions provided by CTI applications
Computer-phone connections can be split into two categories:
;First-party call control
;Third-party call control

History and main CTI technologies

The origins of CTI can be found in simple screen population technology. This allows data collected from the telephone systems to be used as input data to query databases with customer information and populate that data instantaneously in the customer service representative screen. The net effect is the agent already has the required screen on his/her terminal before speaking with the customer.
This technology started gaining widespread adoption in markets like North America and West European countries.
There were several standards which had a major impact in the ´normalization´ of in the industry, previously fully closed and proprietary to each PBX/ACD vendor. On the software level, the most adopted interface by vendors is the CSTA standard, which is approved by the standards body ITU. Other well known CTI standards in the industry are JTAPI, TSAPI and TAPI: JTAPI, the Java Telephony API is promoted by Sun; TSAPI, originally promoted by the AT&T and Novell; Microsoft pushed their own initiative also, and thus TAPI was born, with support mostly from Windows applications. All of these standards required the PBX vendor to write a specific driver, and initially support for this was slow.
Among the key players in this area, Lucent played a big role and IBM acquired ROLM Inc, a US pioneer in ACDs, in an attempt to normalize all major PBX vendor interfaces with its CallPath middleware. This attempt failed when it sold this company to Siemens AG and gradually divested in the area. A pioneer startup that combined the technologies of voice digitization, Token Ring networking, and time-division multiplexing was ZTEL of Wilmington, Massachusetts. ZTEL's computer-based voice and data network combined user-programmable voice call processing features, protocol conversion for automated "data call processing," database-driven directory and telset definitions, and custom LSI chipset technology. ZTEL ceased operation in 1986.
Two other important players were Digital Equipment Corporation and Tiger Software. Digital Equipment Corporation developed CT Connect which includes vendor abstraction middleware. CT Connect was then sold to Dialogic, which in turn was purchased by Intel. This CTI software, known as CT Connect, was most recently sold in 2005 to Envox Worldwide. Tiger Software produced the SmartServer suite which was primarily aimed at allowing CRM application vendors to add CTI functionality to their existing applications with minimal effort. Later, and after changing their name to Mondago, Tiger Software went on to produce the Go Connect server application, which is aimed at providing at helping other CTI vendors integrate with a wider range of telephone systems.
By 2008, most PBX vendors had aligned themselves behind one or two of the TAPI, CSTA or TSAPI standard. The TSAPI advocates were: Avaya, Telrad. The CSTA advocates were: Siemens, Aastra, DeTeWe, Toshiba, Panasonic. The majority preferred TAPI. A few vendors promoted proprietary standards: Mitel, Broadsoft, Digium and most hosted platforms. CT Connect and Go Connect thus provided an important translation middle-layer, allowing the PBX to communicate in its preferred protocol, while an application can communicate using its preferred protocol.
Many of the early CTI vendors and developers have changed hands over the years. An example is Nabnasset, an Acton, Massachusetts firm that developed a CORBA based CTI solution for a client and then decided to make it into a general product. It merged with Quintus, a customer relationship management company, which went bankrupt and was purchased by Avaya Telecommunications. Smaller organisations have also survived from the early days and have leveraged their heritage to thrive. However, many of the 1980s startups that were inspired by the "Bell Breakup" and the coming competitive telephony marketplace, did not survive the decade.
On the hardware level, there was a paradigm shift since 1993, with emerging standards from IETF, which led to several new players like Dialogic, Brooktrout, Natural MicroSystems and Aculab offering telephony interfacing boards for various networks and elements.
Until 2011, it was the makers of telephone systems that implemented CTI technologies such as TAPI and CSTA. But after this time, a wave of handsets become popular that were independently made. These handsets would connect to the telephone systems using standards such as SIP and consumers could easily buy their telephone system from one vendor and their handsets from another. However, this situation led to poor quality CTI since the protocols were not really suitable for third-party control.
So, handset vendors started to add support for CTI directly. Initially this would be over proprietary HTTP methods, but in time uaCSTA became popular and by 2016 most SIP handsets support uaCSTA control. These include: Snom, Yealink, Akuvox, Panasonic and Aastra.