- Email: [email protected]
Advantages of speech over text
Advantagesof speechover text Voicemessagingvs electronicmail by MIKE LACEY
B
efore there was the written word there was the spoken ‘word. Despite the proliferation of devices for inscribing words which have been developed over the centuries, the spoken word remains supreme even in this modern, technologically-orientated. Communication is so much more than words. Face-to-face meetings remain the preferred way of doing important business. The face-to-face meeting is information-rich - take away the eye-to-eye contact through videoconferencing, for example, and some of that richness is lost. Then
Abstract: The value of voiceas a communicationsmedium is undisputed. This paper looks at what voice messaging systems are and their place in relation to text-based messaging systems.It concludes that each has itsplace and the keys to the effective use of each include selecting a community of need and providing appropriatefacilities. In the longer term the medium will become less important and apparent. Keywords: data processing, voice messaging, communications. Mike Lacey Ltd, author systems and evaluate the departments.
10
0011-684X/85/080010-05$03.00
@ 1985 Butterworth
is a principal consultant with Eosys of Eosy’s report on voice messaging leader of a project for the CCTA to use of such systems in government
& Co (Publishers)
Ltd.
take away any sort of image, and all facial expressions and body language are lost too. We’re left with just a voice. However, a voice with its unique qualities, inflections and intonation is a garden of roses compared with the desert of the written word such as you are reading now. What does a memo from the managing director mean which says, ‘See me 10 a.m. Monday morning?’ A bouquet or a brickbat? If he had given the message orally, there would be no doubt. So, in looking at voice messaging, we are looking at a communications medium which is more natural and information-rich than any written or electronic mail system. The theory is therefore that it will be used more naturally than these alternatives. However, as we shall see, sometimes the technology gets in the way.
The telephone The telephone system is a success because it is quicker, and more convenient, constructive and sociable to ring rather than write. Business telephone installations are large and complex. The switchboard (PABX) has to be of a suitable size and type to handle the foreseen numbers of lines and extensions. A grade of service of P.02 is usually specified. That simply
data processing
communications I Delta modulation reconstruction
means that in the busiest period of the day there is no worse than a 2% probability of being unable to make a call. However, problems in making calls do not usually arise at the PABX. They usually occur at the other end in actually making contact with the person to whom you wish to speak. the US statistics are now almost folklore, and stand up fairly well in the light of UK experiece. Only one call in four actually reaches the person you’re trying to contact the first time. Try for yourself for a few days, a sticky label on or by the phone divided into successful and unsuccessful boxes. As you make each call, tick the appropriate box. As well as being a boon, the telephone in business can be a tremendous time-waster. As well as all the time spent in playing ‘telephone tag’, there is a high proportion of social chit-chat in most business calls, and when you receive a call the odds are that it is less important than the work it interrupts - and it can take several minutes to resume the disrupted concentration. It is in response to these sorts of problem that the voice messaging system is presented as a solution.
What is it? A voice messaging system (VMS) is essentially a computer which attaches to the PABX and which stores and replays recorded voice messages. It should not be confused with a telephone answering machine (TAM) which is a precursor of the VMS but has a much more limited function. Many VMS are based on proprietory processors, although some use more familiar computers, such as IBM’s Series/l and the Wang 01s 140. The VMS attaches to a hunt group of PABX extension lines. In the UK it can literally plug into British Telecom white sockets, while in other cases
~0127 no 8
October 1985
Signal Fixed step size
Signal Adaptive step size
I
-1 I1I1IIIIIIIIlIIIIIIIlllIII)
Time
more complicated attachments are required - especially if there is to be any functional integration of the PABX and VMS. Typically, there will be a line card in the VMS handling two or three extensions, recognizing tones and handling the digitization of voice. So larger systems can be built using extra line cards - or extras can be added later as demand builds up. There are then one or more processors controlling the voice messaging system, depending on the information passed from the line cards - together with several Winchester discs. A floppy disc drive is usually included from which to load software and take security copies of parts of the disc relating to system parameters and user profiles. Backups of message storage are usually more infrequent and, given the volumes involved, streamer tape is a more usual medium.
A key to voice messaging systems is the conversion of the speaker’s voice’s waveform to a digital representation Techniques for doing this are now well-established and proven, and good, recognizable reproduction is achieved on playback. Generally, a
continuously variable slope delta modulation technique (CVSD) is used. Figure 1 shows the basic method. Essentially, the difference in frequency between the start and end of a time period is recorded. Early techniques would just indicate an increase or decrease but, as can be seen from the top diagram in Figure 1, it was not possible to follow a rapidly changing waveform accurately. Continuously variable techniques were developed actually to measure the degree of change, giving much better results. Clearly the more often a sample is taken the better fit curve results. Most voice messaging systems on the market sample at 24-32 kbitis (kbps!. Allied with pause compression techniques, to take out the gaps in your speech, these result in storage requirements of around 10 Mbyte of disc per hour. Below 24 kbitis, the quality of speech starts to deteriorate and, while the words are recognizable, the personality of the speaker starts to be lost. Speech compression is an area in which much research and development continues to be invested. One man_%cturer is hoping to put out a voice messaging system later this year with a claimed reduction in storage needs of a factor of three.
11
How is voice messaging used? A familiar situation is where you call a customer, or a colleague, needing to speak to them urgently - only to find that they are in a meeting, or in Amsterdam or just not at their desk. Of course, no one knows when they will be back and no one else can help you. So, frustrated, you leave a message asking them to call you back (they never do) and make yourself a note to call them again tomorrow, A voice messaging systems allows you to leave a recorded message for them in a mailbox to which only they - and perhaps their secretary if they have delegated authority have access. This is like a telephone answering machine, except that the better systems transfer you directly to the appropriate mailbox. If you have a DTMF phone (one that bleeps at you when you press the buttons) you can listen to and rerecord your message if you don’t like it the first time. There are no tapes to jam up and the voice messaging system can inform the mailbox owner that there is a message waiting for him next time he picks up his phone. The latest BABT approvals round in the UK means that most of the available systems can now, with some constraints, dial out - internally or via the Public Switched Telephone Network (PSTN) and attempt to forcibly deliver messages to a predetermined number, such as the Amsterdam office. Where voice messaging systems have been in use for some time, it is common to find callers heading straight for the mailbox rather than even trying to speak to the person directly. This is just one side of the potential use of a voice messaging system that of outsiders trying to contact an individual or individuals. Within an organization there is usually a good deal of information which needs distributing. This will typically go via the internal mail or, if available, some
12
form of electronic mail. Voice messaging systems contain facilities to allow a single recorded message to be broadcast to every mailbox on the system or distributed to a predetermined or ad hoc list of mailboxes. This is an area where a decision needs to be made by the individual sending the message - or the organization as to the most appropriate medium to be used depending on the scope of the distribution, the status of the message, the priority of the message and the cost of distributing it. Table 1 shows some of the strengths and weaknesses of some of the common mail and messaging techniques .
Appropriate systems Voice messaging systems are designed to handle frequent, relatively short messages, which are heard and then deleted. Lengths of messages allowed vary from the sublime (say ten minutes) to the ridiculous (25 seconds). You can’t say very much in 25 seconds - usually just ask one question
or impart one or two facts - you can say too much in ten minutes. Obviously the optimum length for your organization depends on the use to which you are putting it. Clearly any communication of a contractual nature (except for some specialist financial transactions) requires hard copy confirmation. Post and telex (and later teletex) fulfil this need. Facsimile is ideal for the rapid transmission of previously prepared (short) documents which include figures, sketches, graphics and other nontextual material. Text mailboxes provide convenience, where the population exists, for the distribution of textual material, generated on a computer-based system without the necessity for the recipient to be physically present. Text systems generally are good for longer documents which have a structure which needs to be seen by the recipient for ease of comprehension. They are often ‘overkill’ for short messages as the addressing can take longer than the message itself to
data processing
communications enter. Some organizations have found that text mailbox systems are embraced gladly for a year or so, after which they fall into disuse as users become aware that their use has diminished the social interaction vital for an effective working environment. Voice messaging systems come into their own for communications-intensive environments where messages are short and are primarily providing information. They have the added benefit that the intonation of the sender is preserved. Where staff mobility is a prime consideration, they score from not requiring that a bulky terminal is carried with them a small tone generator being sufficient. Problems of order taking can also be overcome by linking the voice messaging system to a voice response system - a technique used by Sperry among others. While voice recording systems are better for short rather than long messages - particularly for the recipient who hears a heavily information-laden message undiluted by the niceties of normal telephone conversations experience in the USA has shown that familiar users gradually increase the length of their messages up to the system’s maximum. One person responsible for a voice messaging system was reported as planning to change the maximum message length back to three minutes from five ‘because they find that people tend to talk for the maximum available time’. That system had been in use for over three years and had almost 3000 users spread across the USA.
Keys There are three keys to the success of a voice messaging system installation. They are also the keys to any sort of messaging, and all the mistakes first made when electronic mail systems were introduced have been made again as voice messaging has been looked on as a technology rather than an applications tool.
~0127 no 8
October 1985
The three keys are: l l l
the need of the community, the capacity of the equipment, the availability of equipment.
At least three of the early voice messaging excursions in the UK ‘failed’ because they were installed for the wrong people. Happily one of those (at the National Coal Board) has been rescued by giving mailboxes to those who really need to communicate with each other. So you really need to find either a group of people within your organization who talk, or would like to talk, to each other a lot, or who the outside world - probably your potential customers is trying to reach. In practice, it is somewhat more complicated than that as most organizations include both groups. So a selected voice messaging system will need to handle both adequately, which overlaps onto the second key that of capacity. As with a PABX or any sort of computer, the capacity (sizing) of a voice messaging system is critical. Can it cope with the messaging needs of the community, both initially and as they get used to it? But also does it have the capacity to grow as more mailboxes are added? To some extent this last point can be overcome by the growing ability of voice messaging systems (at least from the same supplier) to work in tandem or networked together - although this can introduce some addressing and message delivery complications. When talking about capacity in relation to a voice messaging system, the primary components are the number of lines between it and the PABX and the amount of disc storage. Here the disciplines of telecommunications and data processing overlap. The sizing of a voice messaging system in terms of lines is like sizing a PABX in terms of users, anticipated busy period traffic and target grade of service. The estimation of disc storage relates to any computer-based application need-
ing to maintain files. The equation is simplified somewhat when selecting a system from a given supplier as only a restricted number of combinations will be available. The third key to a successful installation is the availability of equipment. For text-based electronic mail systems, such as Telecom Gold, this means which contacts have suitable equipment and established mailboxes. For internal electronic mail systems, it is the existing population of terminals - and the cost of installing terminals just for internal e-mail systems generally precludes their justification. For voice messaging systems, it means essentially, ‘Who has got a telephone?’ or, ‘Who can get access to a telephone when they are away from the office?’ The answer to both questions is, usually, ‘Everyone’. For a captive internal community or, say, a salesforce on the road, the use of small tone generators held over the telephone’s mouthpiece is suitable. These contain a keypad similar to that on a push button telephone, which generates standard CCITT Q.23 dual tones when pressed. These are the same tones generated by a modern MF4 telephone as found in most recent PABX installations. The tones are used to control the voice messaging system when recording or retrieving voice messages. Once the call is established between the telephone and the voice messaging system, via the PABX (and probably several intervening BT exchanges) the tones are passed straight through down the speech channel the PABX ignores them until one of the parties signals ‘on-hook’ or ‘recall’. For heavy use, however, it is essential to have MF4 telephones. Some installations have these in parallel with their normal loop disconnect telephones. The call is established using the latter and the tones input on the former. (MF4 telephones cannot be used on direct telephone lines, or with some PABXs at least not without an upgrade). A much neater
13
solution is starting to appear in the form of telephones which are switchable between MF4 and loop disconnect. These ‘dual phones’ enable a caller to establish a call using loop disconnect and then, on depression of a single key, switch to MF4. (The telephone automatically switches back to loop disconnect when you hang UP>.
Experiments of the type, ‘Put it in and see what happens’ or ‘Give it to the senior management’ are almost certainly doomed to failure. It is necessary to plan, monitor and evaluate. Find the group of people with the greatest need, match the system to their current and other potential needs and, if necessary, upgrade your telephone facilities - or buy a stock of tone generators. OA links
While originally appearing as standalone devices attached to a PABX, the voice messaging system is now equally
Notes for authors Copyright Before publication, authors are requested to assign copyright to Butterworth & Co (Publishers) Ltd. This allows the company to sanction reprints of the whole or part of the volume and authorize photocopies. The authors, however, still retain then traditional right to reuse or to veto third party publication.
swiftly becoming a component of an office automation system. Thus, an electronic mail screenbased system can display the senders, and time and date of receipt of voice messages. Using voice synthesis, the voice messaging system can play out the contents of a text mail intray. So, the telephone could become the universal terminal again. The leading proponents of these techniques are DEC, in conjunction with VoiceMail International Inc. although sadly the facilities are only, as yet, available in the USA. IBM, Sperry, Wang and ITL are all at different stages along the same path. Conclusions
Voice messaging is but one tool in the kit available to telecommunications, data processing and administrative managers in solving the problems set them by modern business practices and needs. While in the USA voice
Units You should use, as far as is possible, Sl units. In circumstances where this is not possible, please provide a conversion factor at the first mention of the unit.
14
Eosys Limited, Clove House, The Broadway, Farnham Common, Slough SL2 3PQ, UK.
Photographs Black and white glossy photographs (including Polaroid prints of VDU screens) should, where possible, be supplied unmounted. They should be labelled clearly on the back with a soft pencil.
Illustrations Line drawings We have our own professional studio to ensure that line drawings are consistent with house style. We would prefer, however, to receive unlettered drawings (black ink on tracing paper) so we can put on the lettering ourselves.
Preparation of scripts As you can see from the journal, every article published is stylized by us to keep consistency throughout each volume. We follow the Oxford English Dictionary. It would be helpful if you could follow the journal style. The most important thing, though, is that you write (or rather type) in clear and concise English. Contributions should be typed double-spaced on one side of the paper. We would also appreciate it if you number each page and leave wide margins so we can prepare the article for the typesetters.
messaging is an accepted practice, there are fewer than 20 customer installations in the UK. At present, the benefits are unproven although techniques exist developed from work Eosys has been doing with CCTA - for optimizing envisaged benefits through the concentration on key communities. There is a growing recognition in the UK that voice messaging has a role to play alongside other forms of messaging - although the immature state of development of some of the available systems is hampering their effective use. For the future, the medium of the message will become less important and, as document architectures are transparent. However, developed, there is still a long way to go before that happens and until then it is a case of using appropriate equipment in each given situation. q
References Our journal style is to indicate the use of a reference in the text with a superscript as each one arises and give the full reference with the same number at the end. If a reference is cited more than once, the same number should be used each time. With a bibliography, the references are given in alphabetic order (dependent on the first authors’ surname). It would be helpful if you could follow this style.
Computer printouts Illustrations showing line printer listings, plotter output, et?, should preferably be on unlined paper. Prmtouts will be reduced bv us to the relevant size. Do not mark them as &ill be used to make photographic copies for the typesetters. Only include sufficient lines for the reader to interpret the format and nature of the printout. Overlong printouts only cause confusion. Fuller explanation should appear in the caption and the text.
Reprints The first named author will receive 25 reprints of the technical article free of charge. Further copies, a minimum of 100, can be ordered at any time from the Reprints Department, Butterworth Scientific Ltd, Westbury House, PO Box 63, Bury Street, Guildford, Surrey GU2 5BH, UK.
data processing
B
efore there was the written word there was the spoken ‘word. Despite the proliferation of devices for inscribing words which have been developed over the centuries, the spoken word remains supreme even in this modern, technologically-orientated. Communication is so much more than words. Face-to-face meetings remain the preferred way of doing important business. The face-to-face meeting is information-rich - take away the eye-to-eye contact through videoconferencing, for example, and some of that richness is lost. Then
Abstract: The value of voiceas a communicationsmedium is undisputed. This paper looks at what voice messaging systems are and their place in relation to text-based messaging systems.It concludes that each has itsplace and the keys to the effective use of each include selecting a community of need and providing appropriatefacilities. In the longer term the medium will become less important and apparent. Keywords: data processing, voice messaging, communications. Mike Lacey Ltd, author systems and evaluate the departments.
10
0011-684X/85/080010-05$03.00
@ 1985 Butterworth
is a principal consultant with Eosys of Eosy’s report on voice messaging leader of a project for the CCTA to use of such systems in government
& Co (Publishers)
Ltd.
take away any sort of image, and all facial expressions and body language are lost too. We’re left with just a voice. However, a voice with its unique qualities, inflections and intonation is a garden of roses compared with the desert of the written word such as you are reading now. What does a memo from the managing director mean which says, ‘See me 10 a.m. Monday morning?’ A bouquet or a brickbat? If he had given the message orally, there would be no doubt. So, in looking at voice messaging, we are looking at a communications medium which is more natural and information-rich than any written or electronic mail system. The theory is therefore that it will be used more naturally than these alternatives. However, as we shall see, sometimes the technology gets in the way.
The telephone The telephone system is a success because it is quicker, and more convenient, constructive and sociable to ring rather than write. Business telephone installations are large and complex. The switchboard (PABX) has to be of a suitable size and type to handle the foreseen numbers of lines and extensions. A grade of service of P.02 is usually specified. That simply
data processing
communications I Delta modulation reconstruction
means that in the busiest period of the day there is no worse than a 2% probability of being unable to make a call. However, problems in making calls do not usually arise at the PABX. They usually occur at the other end in actually making contact with the person to whom you wish to speak. the US statistics are now almost folklore, and stand up fairly well in the light of UK experiece. Only one call in four actually reaches the person you’re trying to contact the first time. Try for yourself for a few days, a sticky label on or by the phone divided into successful and unsuccessful boxes. As you make each call, tick the appropriate box. As well as being a boon, the telephone in business can be a tremendous time-waster. As well as all the time spent in playing ‘telephone tag’, there is a high proportion of social chit-chat in most business calls, and when you receive a call the odds are that it is less important than the work it interrupts - and it can take several minutes to resume the disrupted concentration. It is in response to these sorts of problem that the voice messaging system is presented as a solution.
What is it? A voice messaging system (VMS) is essentially a computer which attaches to the PABX and which stores and replays recorded voice messages. It should not be confused with a telephone answering machine (TAM) which is a precursor of the VMS but has a much more limited function. Many VMS are based on proprietory processors, although some use more familiar computers, such as IBM’s Series/l and the Wang 01s 140. The VMS attaches to a hunt group of PABX extension lines. In the UK it can literally plug into British Telecom white sockets, while in other cases
~0127 no 8
October 1985
Signal Fixed step size
Signal Adaptive step size
I
-1 I1I1IIIIIIIIlIIIIIIIlllIII)
Time
more complicated attachments are required - especially if there is to be any functional integration of the PABX and VMS. Typically, there will be a line card in the VMS handling two or three extensions, recognizing tones and handling the digitization of voice. So larger systems can be built using extra line cards - or extras can be added later as demand builds up. There are then one or more processors controlling the voice messaging system, depending on the information passed from the line cards - together with several Winchester discs. A floppy disc drive is usually included from which to load software and take security copies of parts of the disc relating to system parameters and user profiles. Backups of message storage are usually more infrequent and, given the volumes involved, streamer tape is a more usual medium.
A key to voice messaging systems is the conversion of the speaker’s voice’s waveform to a digital representation Techniques for doing this are now well-established and proven, and good, recognizable reproduction is achieved on playback. Generally, a
continuously variable slope delta modulation technique (CVSD) is used. Figure 1 shows the basic method. Essentially, the difference in frequency between the start and end of a time period is recorded. Early techniques would just indicate an increase or decrease but, as can be seen from the top diagram in Figure 1, it was not possible to follow a rapidly changing waveform accurately. Continuously variable techniques were developed actually to measure the degree of change, giving much better results. Clearly the more often a sample is taken the better fit curve results. Most voice messaging systems on the market sample at 24-32 kbitis (kbps!. Allied with pause compression techniques, to take out the gaps in your speech, these result in storage requirements of around 10 Mbyte of disc per hour. Below 24 kbitis, the quality of speech starts to deteriorate and, while the words are recognizable, the personality of the speaker starts to be lost. Speech compression is an area in which much research and development continues to be invested. One man_%cturer is hoping to put out a voice messaging system later this year with a claimed reduction in storage needs of a factor of three.
11
How is voice messaging used? A familiar situation is where you call a customer, or a colleague, needing to speak to them urgently - only to find that they are in a meeting, or in Amsterdam or just not at their desk. Of course, no one knows when they will be back and no one else can help you. So, frustrated, you leave a message asking them to call you back (they never do) and make yourself a note to call them again tomorrow, A voice messaging systems allows you to leave a recorded message for them in a mailbox to which only they - and perhaps their secretary if they have delegated authority have access. This is like a telephone answering machine, except that the better systems transfer you directly to the appropriate mailbox. If you have a DTMF phone (one that bleeps at you when you press the buttons) you can listen to and rerecord your message if you don’t like it the first time. There are no tapes to jam up and the voice messaging system can inform the mailbox owner that there is a message waiting for him next time he picks up his phone. The latest BABT approvals round in the UK means that most of the available systems can now, with some constraints, dial out - internally or via the Public Switched Telephone Network (PSTN) and attempt to forcibly deliver messages to a predetermined number, such as the Amsterdam office. Where voice messaging systems have been in use for some time, it is common to find callers heading straight for the mailbox rather than even trying to speak to the person directly. This is just one side of the potential use of a voice messaging system that of outsiders trying to contact an individual or individuals. Within an organization there is usually a good deal of information which needs distributing. This will typically go via the internal mail or, if available, some
12
form of electronic mail. Voice messaging systems contain facilities to allow a single recorded message to be broadcast to every mailbox on the system or distributed to a predetermined or ad hoc list of mailboxes. This is an area where a decision needs to be made by the individual sending the message - or the organization as to the most appropriate medium to be used depending on the scope of the distribution, the status of the message, the priority of the message and the cost of distributing it. Table 1 shows some of the strengths and weaknesses of some of the common mail and messaging techniques .
Appropriate systems Voice messaging systems are designed to handle frequent, relatively short messages, which are heard and then deleted. Lengths of messages allowed vary from the sublime (say ten minutes) to the ridiculous (25 seconds). You can’t say very much in 25 seconds - usually just ask one question
or impart one or two facts - you can say too much in ten minutes. Obviously the optimum length for your organization depends on the use to which you are putting it. Clearly any communication of a contractual nature (except for some specialist financial transactions) requires hard copy confirmation. Post and telex (and later teletex) fulfil this need. Facsimile is ideal for the rapid transmission of previously prepared (short) documents which include figures, sketches, graphics and other nontextual material. Text mailboxes provide convenience, where the population exists, for the distribution of textual material, generated on a computer-based system without the necessity for the recipient to be physically present. Text systems generally are good for longer documents which have a structure which needs to be seen by the recipient for ease of comprehension. They are often ‘overkill’ for short messages as the addressing can take longer than the message itself to
data processing
communications enter. Some organizations have found that text mailbox systems are embraced gladly for a year or so, after which they fall into disuse as users become aware that their use has diminished the social interaction vital for an effective working environment. Voice messaging systems come into their own for communications-intensive environments where messages are short and are primarily providing information. They have the added benefit that the intonation of the sender is preserved. Where staff mobility is a prime consideration, they score from not requiring that a bulky terminal is carried with them a small tone generator being sufficient. Problems of order taking can also be overcome by linking the voice messaging system to a voice response system - a technique used by Sperry among others. While voice recording systems are better for short rather than long messages - particularly for the recipient who hears a heavily information-laden message undiluted by the niceties of normal telephone conversations experience in the USA has shown that familiar users gradually increase the length of their messages up to the system’s maximum. One person responsible for a voice messaging system was reported as planning to change the maximum message length back to three minutes from five ‘because they find that people tend to talk for the maximum available time’. That system had been in use for over three years and had almost 3000 users spread across the USA.
Keys There are three keys to the success of a voice messaging system installation. They are also the keys to any sort of messaging, and all the mistakes first made when electronic mail systems were introduced have been made again as voice messaging has been looked on as a technology rather than an applications tool.
~0127 no 8
October 1985
The three keys are: l l l
the need of the community, the capacity of the equipment, the availability of equipment.
At least three of the early voice messaging excursions in the UK ‘failed’ because they were installed for the wrong people. Happily one of those (at the National Coal Board) has been rescued by giving mailboxes to those who really need to communicate with each other. So you really need to find either a group of people within your organization who talk, or would like to talk, to each other a lot, or who the outside world - probably your potential customers is trying to reach. In practice, it is somewhat more complicated than that as most organizations include both groups. So a selected voice messaging system will need to handle both adequately, which overlaps onto the second key that of capacity. As with a PABX or any sort of computer, the capacity (sizing) of a voice messaging system is critical. Can it cope with the messaging needs of the community, both initially and as they get used to it? But also does it have the capacity to grow as more mailboxes are added? To some extent this last point can be overcome by the growing ability of voice messaging systems (at least from the same supplier) to work in tandem or networked together - although this can introduce some addressing and message delivery complications. When talking about capacity in relation to a voice messaging system, the primary components are the number of lines between it and the PABX and the amount of disc storage. Here the disciplines of telecommunications and data processing overlap. The sizing of a voice messaging system in terms of lines is like sizing a PABX in terms of users, anticipated busy period traffic and target grade of service. The estimation of disc storage relates to any computer-based application need-
ing to maintain files. The equation is simplified somewhat when selecting a system from a given supplier as only a restricted number of combinations will be available. The third key to a successful installation is the availability of equipment. For text-based electronic mail systems, such as Telecom Gold, this means which contacts have suitable equipment and established mailboxes. For internal electronic mail systems, it is the existing population of terminals - and the cost of installing terminals just for internal e-mail systems generally precludes their justification. For voice messaging systems, it means essentially, ‘Who has got a telephone?’ or, ‘Who can get access to a telephone when they are away from the office?’ The answer to both questions is, usually, ‘Everyone’. For a captive internal community or, say, a salesforce on the road, the use of small tone generators held over the telephone’s mouthpiece is suitable. These contain a keypad similar to that on a push button telephone, which generates standard CCITT Q.23 dual tones when pressed. These are the same tones generated by a modern MF4 telephone as found in most recent PABX installations. The tones are used to control the voice messaging system when recording or retrieving voice messages. Once the call is established between the telephone and the voice messaging system, via the PABX (and probably several intervening BT exchanges) the tones are passed straight through down the speech channel the PABX ignores them until one of the parties signals ‘on-hook’ or ‘recall’. For heavy use, however, it is essential to have MF4 telephones. Some installations have these in parallel with their normal loop disconnect telephones. The call is established using the latter and the tones input on the former. (MF4 telephones cannot be used on direct telephone lines, or with some PABXs at least not without an upgrade). A much neater
13
solution is starting to appear in the form of telephones which are switchable between MF4 and loop disconnect. These ‘dual phones’ enable a caller to establish a call using loop disconnect and then, on depression of a single key, switch to MF4. (The telephone automatically switches back to loop disconnect when you hang UP>.
Experiments of the type, ‘Put it in and see what happens’ or ‘Give it to the senior management’ are almost certainly doomed to failure. It is necessary to plan, monitor and evaluate. Find the group of people with the greatest need, match the system to their current and other potential needs and, if necessary, upgrade your telephone facilities - or buy a stock of tone generators. OA links
While originally appearing as standalone devices attached to a PABX, the voice messaging system is now equally
Notes for authors Copyright Before publication, authors are requested to assign copyright to Butterworth & Co (Publishers) Ltd. This allows the company to sanction reprints of the whole or part of the volume and authorize photocopies. The authors, however, still retain then traditional right to reuse or to veto third party publication.
swiftly becoming a component of an office automation system. Thus, an electronic mail screenbased system can display the senders, and time and date of receipt of voice messages. Using voice synthesis, the voice messaging system can play out the contents of a text mail intray. So, the telephone could become the universal terminal again. The leading proponents of these techniques are DEC, in conjunction with VoiceMail International Inc. although sadly the facilities are only, as yet, available in the USA. IBM, Sperry, Wang and ITL are all at different stages along the same path. Conclusions
Voice messaging is but one tool in the kit available to telecommunications, data processing and administrative managers in solving the problems set them by modern business practices and needs. While in the USA voice
Units You should use, as far as is possible, Sl units. In circumstances where this is not possible, please provide a conversion factor at the first mention of the unit.
14
Eosys Limited, Clove House, The Broadway, Farnham Common, Slough SL2 3PQ, UK.
Photographs Black and white glossy photographs (including Polaroid prints of VDU screens) should, where possible, be supplied unmounted. They should be labelled clearly on the back with a soft pencil.
Illustrations Line drawings We have our own professional studio to ensure that line drawings are consistent with house style. We would prefer, however, to receive unlettered drawings (black ink on tracing paper) so we can put on the lettering ourselves.
Preparation of scripts As you can see from the journal, every article published is stylized by us to keep consistency throughout each volume. We follow the Oxford English Dictionary. It would be helpful if you could follow the journal style. The most important thing, though, is that you write (or rather type) in clear and concise English. Contributions should be typed double-spaced on one side of the paper. We would also appreciate it if you number each page and leave wide margins so we can prepare the article for the typesetters.
messaging is an accepted practice, there are fewer than 20 customer installations in the UK. At present, the benefits are unproven although techniques exist developed from work Eosys has been doing with CCTA - for optimizing envisaged benefits through the concentration on key communities. There is a growing recognition in the UK that voice messaging has a role to play alongside other forms of messaging - although the immature state of development of some of the available systems is hampering their effective use. For the future, the medium of the message will become less important and, as document architectures are transparent. However, developed, there is still a long way to go before that happens and until then it is a case of using appropriate equipment in each given situation. q
References Our journal style is to indicate the use of a reference in the text with a superscript as each one arises and give the full reference with the same number at the end. If a reference is cited more than once, the same number should be used each time. With a bibliography, the references are given in alphabetic order (dependent on the first authors’ surname). It would be helpful if you could follow this style.
Computer printouts Illustrations showing line printer listings, plotter output, et?, should preferably be on unlined paper. Prmtouts will be reduced bv us to the relevant size. Do not mark them as &ill be used to make photographic copies for the typesetters. Only include sufficient lines for the reader to interpret the format and nature of the printout. Overlong printouts only cause confusion. Fuller explanation should appear in the caption and the text.
Reprints The first named author will receive 25 reprints of the technical article free of charge. Further copies, a minimum of 100, can be ordered at any time from the Reprints Department, Butterworth Scientific Ltd, Westbury House, PO Box 63, Bury Street, Guildford, Surrey GU2 5BH, UK.
data processing