Open Architecture Computer Telephony Servers and Tools

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ANALOGUE LINES Versus DIGITAL LINES

The minimum line configuration for CallHandler is 4 lines using 4 off analogue line connections. At this level its potential is not maximised, but, remember, CallHandler is 'infinitely' scalable, so there is an option to start small and expand the system as your business grows - both in terms of number of lines, and system functionality. If you are going to use CallHandler with digital line input, there needs to be an ISDN digital point of connection - analogue telephone ports won't work. Remember, your callers can still use analogue phones, but CallHandler for Basic Rate or Primary Rate ISDN needs a digital input.

This section uses a series of diagrams to help you understand when the use of digital lines are more appropriate than analogue. Your application may function adequately on an analogue system - its not until you upgrade to digital lines that CallHandler can be used. Basic computer telephony system configurations are described, starting with a simple fax system and building up to a comprehensive voice based CallHandler system. Fax is used in the example because it is simple to understand, but this represents only a fraction of the capability of the CallHandler system.

Single Modem Connectivity

The diagram below shows an Internet application, which effectively is the connection of two or more computers together over a telephone network. The digital computers are connected via digital to analogue converters (modems) to the standard telephone network. This is then converted back to a digital format for routing through the network. This application represents an example of basic Computer Telephony Integration.

Fax-Back Four Modem System

In this example of a Fax Back system, four modems are connected to the PC and to four analogue incoming lines. A caller is connected to the computer by dialling a pre-set number. The computer answers the call and can either respond directly by transmitting a fax, or can be guided through a voice script in combination with use of a touch-tone to select the required fax. This fax could be a report from data contained within a database either on the PC or some other PC, which is connected via a data network. It could also be a fax document transmitted to the fax-back system from a remote fax machine, and stored on the PC.

Fax-Back Twenty Line System

The number of lines connected to the PC depends of the density of the call traffic expected. The main criteria being how many times you want the caller to experience an engaged tone. (Remember, if you are making money from the calls, an engaged tone is effectively costing you money). As the number of lines increases so does both the cost of both the implementation in hardware of the modem system. Also the cost of having individual analogue lines installed at a point close to the PC, but overall the cost per line should drop the more lines that are installed. For a ten line system, for example, it makes sense to get connected to a digital ISDN line. Telecommunications companies, such as British Telecom, provide access to multiple ISDN lines via an E1 (T1 in North America) connection. This is a cable, which can be laid to your office/house to provide up to 30 lines of discrete telephone channels. To connect to this E1 socket specialist PC hardware is required. These are sometimes called (telephone) Network cards and they plug into the PC like normal PC Cards.

Very Important Note: because this is a digital system the CallHandler PC can send up to 60 simultaneous FAXes without the need for special modems. Since the same hardware is capable of many other functions, it can be used for a multiplicity of applications by adding additional controlling software modules. For example it can be used as a voice activated Telephone Information System during working hours, and during off peak periods, it can broadcast FAXes for advertising purposes. It could even be programmed to do random dialling to establish if a fax exists. If a fax is detected this can be then entered into a database for later use in the FAX mail-shot.

Adding Functionality

The functionality of the CallHandler System is dependent on who or what it is connected to. If is a gambler calling, then it has the functionality and scripting set-up consistent with telephone gambling. If it is connected to a web page, it has the functionality associated with interfacing with a web page. In general the caller interfaces with a script which is a series of voice prompts which are played to the caller in response to certain key presses. This script is the interface between the caller and the required functionality required; be it fax on demand or voice communications between two people. The response to the script by the caller can either be by telephone key press or voice where the computer operates simple voice recognition. The service operator defines how they want the caller to interface to the computer, and this is implemented by adding the relevant hardware and software modules.

Important Note: Computers have a wide range of functionality. Whatever the functionality of the PC, this can be made to integrate with the telephone network and the device at the other end - whether it be called, or calling. The only limitation is the volume of data that to be transmitted between the two ends of the communication. Video for example requires quite high data throughput (Bandwidth) and so higher capacity Telephone Networks (such as ATM) may be required to enable the communications. This would require additional hardware in the CallHandler, but the principals are the same. General rule: think of a computer application and this can almost certainly be integrated into a CallHandler System.

Summary:

When choosing a CallHandler system there are three important considerations,

CallHandler only supports connection to the public telephone network via digital (ISDN) connections. Callers who are connected to the telephone network via analogue lines can still communicate via the CallHandler.
How many simultaneous telephone connections your business requirements need. This is sometimes called the call density. This has cost implications – the higher the call density the lower the cost per line. Also, in an example where a 30 line CallHandler system is being used, its important to remember that CallHandler can be upgraded simply by adding extra hardware, and/or software modules.
The functionality of the system – this relates to the types of applications, which can be supported. Each unique hardware and software module provides additional modularity. Choose CallHandler because is has high functionality.

In the above examples to illustrate the principles of CallHandler systems, simple FAX examples were used. The same principles can be applied to a voice system and many other types of computer telephony related applications. FAX and voice can be operated simultaneously in the same system. Chelston”s CallHandler system is a general purpose system which can be configured to a very wide variety of application – the choice is yours.

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Chelston Call Systems Ltd.
49 Dove Park, Chorleywood, Hertfordshire, England, WD3 5NY
Tel: 01923 286501 - Fax: 01923 286498
Located just north of Heathrow Airport, London
Email: info@Chelston.co.uk