Digital Dictation and Transcription Systems

Bruce Stockwell of BVP Computers is an electronics engineer by education. He taught advanced electronics in the United States Marine Corps and then went to Vietnam. Prior to starting BVP in 1987, he was the executive vice president for a multinational cable television company.
Computers...101-1, ISDN & Transcription

I. What is Digital?
It is necessary to understand some brief and simple concepts concerning computers BEFORE we can understand ISDN as it relates to transcription. All computers, from the most powerful super computer to our own PCs operate on the same foundational aspects. They are digital devices. We sometimes let certain words intimidate us. This "digital" word should not be one. We work with digital devices every day even if we do not own a computer.

We come home at night and we flip on the porch light...we have just used a digital device. (This assumes the light switch was a regular toggle switch ...not a special dimmer switch) For our understanding, a digital device can only exist in one of two possible states(conditions)....ON or OFF. The porch light will always be either ON or OFF.

This on-off state or condition is defined as a binary state. Webster defines binary as "...a CHOICE between or condition of two alternatives ONLY..." In other words, it can only exist in ONE of two possible states...ON or OFF.

Computers have millions of tiny "porch light switches" that are either ON or OFF. All of our computer programs, files, voice dictations, data either ON or OFF. All of our computer programs, files, voice dictations, data etc are represented by nothing more than combinations of these switches being ON or OFF. Let's further consider that when the light swith is OFF it is (0) zero and when the light switch is ON it is something that we will call a 1 (one). We have just learned the two possible states that a binary device can exist in ... OFF or 0 and ON or 1. This is precisely what binary devices do ... they exist as a 0 or a 1. So our porch light, when viewed as a binary device, is a 0 when it is off and a 1 when it is on.

We can say the light switch is 0 ... or we can say the light switch is OFF...BOTH mean exactly the same thing. But notice that saying it is 0 has saved us from typing two characters (the FF of OFF). As long as we ALL know that 0=OFF then when anyone of us talks about the light switch being 0 we all know that we really mean it is OFF. With only two characters (0 or 1) we are representating the condition of the light switch. Congratualations! You have just learned what a digital/binary "bit" is. A bit is either a 0 or a 1, in our case representing if our light is on or off. 0 is a digital bit...1 is a digital bit.

However, a single digital bit has a limited can only represent one of two possible conditions, on or off. This compares to a yes or no question...not maybe. Not too great for the complex functions that are required in our computers. Ah, but if we combine some bits together, we will see how we can build some very powerful capabilities.

Associations: We all make them, they are very common. He/she is tall, thin, smart etc. When you read those words you had a flash vision in your mind of somthing/someone that you associated with the word. It might take "a thousand" words to explain the picture you saw, but it got you there, with a one word association. This is similar to the "LINKS" on the internet, where one word might link to or "represent" thousands of other words. When we say "the Webster Dictionary" it is only a 22 character phrase, yet we can associate that the phrase might represent most all of the words used in our entire language. So it is, with combinations of bits...they can be used to represent more powerful information.

Let's look at a simple decimal number: 123. We can see that there are three digits or numbers. Our "normal" numbering system is called a decimal base 10 system. Each digit can represent a value from 0 to 9. We can obtain more powerful numbers by putting multiple digits together, like the above 123 number. We say the 3 is in the unit position, the 2 is in the tens position and the 1 is in the hundreds position. This "position" simply establishes the value or "power" depending on WHERE the digit is located. Starting from right to left, the right most position is the "least important" and the left most position is the "most important". We now see that the physical location or placement of the digits is VERY important! We will, for simplicity, refer to the digit 3 as being in position 1, the digit 2 in position 2 and the digit 1 in position 3.

If we doubt this importance, let's consider the following. I offer you the maximum amount of money represented by any digit POSITION of the above three digits (123). Which one would you choose? Of course we would choose position 3 which is the actually the digit 1. In this position we are talking hundreds of dollars when compared to position 1 that could only represent to us a maximum of nine dollars. Even though the digit 3 is numerically larger than the digit 1, the digit 1 POSITION has made it "more valuable" or more important to us.

Even though our number (123) has only three digits it actually REPRESENTS one hundred and twenty three INDIVIDUAL unique things to us, all with just three digits. When we combine bits, there is a relationship of the "importance" of bit positions, just like our decimal numbering system. Combining bits to represent other information works great IF "EVERYONE" knows, agrees and operates from the SAME definition of the bit pattern. What we mean is, if to a computer, 01011 means, "Hello to all the peoples of the world," then it must mean the same thing ALL of the time EVERY time.

You may have heard about computer incompatibilities. This can occur when a computer does not process a series of bits exactly the same way as another computer. Therefore different results are obtained. Sometimes pretty bad! Taking our example from above, 01011 meant, "Hello to all the peoples of the world". But if the other computer "thinks" it means, "Hello AT all the peoples of the world," we are in deep trouble.

The 01011 can actually mean different things at different times! It depends on what the computer has been "told" to do with the bit pattern at the time that it processes it. In your word processor, it might represent a character, but in your spreadsheet it might be a comannd to do something. Not as strange or confusing as it might first appear. When we talk to someone we might say "cool" if we meant neat, super, etc. But we might respond "cool" when we were asked for the temperature. Different siutations determined how we interpreted the "cool;" it is the same with the computer.

You may not have heard the word bit before, but if you use computers, a more common term you might have heard is a byte. A byte is simply 8 bits combined and referred to as a byte: 8 bits=1 byte and 1 byte=8 bits. 8 bits will have 8 positions ie: 01010101 is a byte so is 00000000 so is 11111111. It is 8 total bits, each bit could be a 0 or a 1. Bytes relate to your data, programs, files, etc. When you save a word processor data file that has your completed transcription to the hard disk, it saves it in bytes. Let's say we named our completed transcription file as doctor7.txt. When we ask the computer to show us information about this file (not the actual contents of the file) we can learn the date, time and the number of BYTES that comprise the file. Let's say the doctor7.txt file has 10,000 bytes. Most word processors use 8 bits (1 byte) to represent a character (letter-number-space-comma etc) so we might "assume" that the file has 10,000 characters. This may or may not be true depending upon your word processor. It DOES contain 10,000 bytes but many may be header information, font information, printer info etc. This same 10,000 bytes could also be said to contain 80,000 bits. (10,000 bytes times 8 bits per byte...10,000 bytes = 80,000 bits...80,000 bits = 10,000 bytes)

It took all of above to give you an explanation that will be VERY important when we look at ISDN as it relates to transcription. Keep in mind what a bit is: 0 or 1, and that a byte equals 8 bits.

II. It's an Analog World

In our last session, we learned about our computers operating in digital or binary states. These states could be described as black or white, but no gray. The binary state reflected a condition of being either "on" or "off".

The "real world" that we live in is not just black and white. It is never simply "on" or "off". It is a myriad of ever changing colors, conditions and circumstances. When we we speak, the very words we hear are an ever-changing pattern. These changing or varying conditions are described by a technical term we call "analog".

A digital wave can be visualized as a box which would have straight sides, a flat bottom and a flat top. An analog wave might be compared to a grapefruit which would have curved sides, a rounded top and a rounded bottom. Due to the limitations of a text-only presentation, it might be difficult to visualize this digital and analog wave comparision. Therefore, we would like to invite you to view a picture of this representation. Please consider visiting our web site at URL:

From the home page select the "How?" button and then the "Next" button. The graphic you should now be viewing is called "More Technical".

The wave on the left, under the woman, is called an analog wave. This is the type of wave that our speech would look like. The wave pattern in the center, under the computer, is digital and shows how our computers represent information. We generally refer to digital waves as "square waves" and the analog form of waves are called a "sine waves".

It is important that we understand these distinctions, as the type of wave that we are interested in processing can largely determine the method we use to process it. It would be erroneous to say that analog is better than digital or that digital is better than analog, each has its place. It would be more appropriate to consider that each has a specific purpose, based upon the intended application. Consider a hammer and a screwdriver. If you need a screwdriver, a hammer is pretty useless. Each tool has a particular purpose to which it is best suited.

Here are a few real-world examples that use sine waves: our speech, standard telephones, radio, television, tape player and touch-tone telephone.

We can convert one type of wave to another for the purpose of allowing an analog device to handle a converted square wave or a digital device a converted analog wave. In this conversion, the analog waves become digital waves and the digital waves become analog waves. Why would we want to do this? If we need to move information that is digital, through a media that prevails throughout the entire world, and that media is analog, it would not be feasible to change the entire world, but instead the digital information. This is precisely what we do.

Let's consider our standard telephone network. Although it is being improved daily, it is still currently considered an analog system. It is only capable of handling sine waves. You might say, "Now wait a minute, I'm sending stuff from my digital computer into the phone system and around the world." You would be quite correct with this statement, with the exception being that you are not sending digital information directly.

A device is connected to your computer called a modem which converts the computers digital data into analog sine waves so that the telephone network can handle the information. (This process is reversed on the receiving end.) This has worked well for many years, but it has certain inherent limitations. Our need to transmit more data and at a faster rate has and will continue to grow. The existing analog telephone network is, by design, limited to a little over 50KBS. The "K" stands for kilo or 1000. The "B" stands for bits and the "S" stands for seconds. So, we are saying that the most we can send down the telephone network is a little over 50,000 bits per second. (Remember, a bit is a "0" or a "1".) Currently, standard modem products are available that send information at 28.8KBS. (We can also use some compression and an error checking algorithm to increase the effective through-put.)

Compression is a way of making our data smaller for quick transfer and then it is reconstructed at the point of receipt. There are two main classes of compression, Loss-less and with loss. In the loss-less type all data is rebuilt exactly as the original file. In the other, it will not contain all of the exact information. We would use loss-less for our data or programs and we might use the loss type for a video or graphics where a few missing bytes would generally not be detrimental.

Nationally, we are about to reach a maximum transmission rate ceiling for our telephone system. We call the existing analog telephone network POTS (Plain Old Telephone Service). Does this mean all is lost? No, actions have and are being taken to provide for more and better phone service capabilities. The current most cost viable consideration is for the use of an optional service called ISDN (Integrated Services Digital Network). In our next installment we will discuss the purpose, use and benefits of ISDN as it relates to Dictation & Transcription.

3. What is ISDN?

ISDN (Integrated Services Digital Network) is a relatively new optional phone service that is available in most areas of the United States.

Previously, we learned that our standard phone system is called POTS (Plain Old Telephone Service). This POTS is an analog service. For many people, this service is more than ample to meet their communication needs. It is simple to use and has lots of ine xpensive standard hardware devices available for use on the POTS.

In contrast, ISDN is a digital service. It has a much higher bandwidth than the POTS. The wider the bandwidth the more information we can send. The POTS system is currently limited to about 56KB/S tops; ISDN will yield 128KB/S. One of the GREAT benefits of sending digital information down a digital network, like IS DN, is that it is NOT as susceptible to "noise" as is an analog signal. The term noise refers to electrical disturbances (clicks, pops, etc) that are common during transmission. Analog signals are more prone to being affected by this noise. This noise can actually alter the information that is being transmitted.

Before we discuss ISDN details, it is IMPORTANT to note that getting ISDN service installed and functioning is NOT for the faint of heart! There are numerous "horror" stories of botched installations, incompatibilities, etc., etc. This caution is NOT meant to discourage you from getting the service, but is stated as a caution to be VERY careful every step of the way! Buyer beware! If the system is properly installed with the RIGHT equipment, it will be a great asset to your operation. The actual ISDN serv ice will be installed by your local phone company and certain "inside" equipment will be YOUR responsibility to provide and install. There is a SHORTAGE of phone company personnel that are qualified to install/maintain the ISDN service in many cities. Enough said?

The ISDN service is an "on-demand" service or more commonly called a switched service. This means it summons a connection only when there is a demand. (The POTS system is switched as well.) A common configuration for ISDN will yield 128KB/S, more that FOU R TIMES the speed of a standard 28.8KB/S analog modem. A "normal" configuration might be two "B" (Bearer) channels, each of 64KB/S and bonded together for a 128KB/S data path. In this configuration there is also a "D" (Data) channel which handles setup an d signaling information. This type of configuration is called a BRI (Basic Rate Interface) ISDN connection. It is probably the more common type of configuration.

Installation costs vary but generally are in the range of $100©300 and the monthly service fee from about $25©75 per month. PLUS many/most phone companies will charge you per minute and/or per data amount and may be on a per "B" channel basis. The best ad vice we can give you is to be SURE you understand all of the billingÔ We will talk in general terms concerning ISDN, as there are many variables, depending upon your individual phone service provider. You should first contact your phone company and make SURE that ISDN is available for your home or business. Next, you must work BACKWARDS when ordering the ISDN service. By this we mean you get the inside equipment FIRST, then you order the ISDN service from your phone company. Later, we will discuss the equipment you will need.

When you order the inside equipment, MAKE the company you are purchasing the equipment from provide you with a COMPLETE set of ISDN ordering parameters and specifications. You will then present these to your phone company. Your phone company will then configure your ISDN connection to these parameters and specificat ions. You must not do these steps backwards!

At your home or office, YOU must provide a NT1 (network termination 1) device and you will need a Terminal Adapter device (TA) to adapt to RS-232 (the serial port on your PC). This equipment may come combined in one PC card or a special modem. You may want to add digital phones as well. Remember your standard analog phone s and equipment will NOT work directly on ISDN. If you are not a "rocket scientist", you may want to obtain some technical assistance from a QUALIFIED ISDN equipment installing computer dealer in your area. Be sure to obtain a written quote describing wha t the dealer will do and what they will charge you to do it. They may also act as a liaison with your phone company.

Your computer should be at LEAST an 80486-DX-33Mhz and the serial port must be a 16550 UART (Universal Asynchronous Receiver and Transmitter) if you will be using an external ISDN modem.

If you choose to follow the above tips and suggestions, you will help to insure that the ISDN installation is as painless as possible. Though not a complete panacea, we hope these suggestions will save you considerable grief.

In our next session, we will cover whether ISDN is a cost viable performance consideration for you.

4. ISDN - Do I need it?

In the previous articles, we learned of the ISDN benefits:
-Clear digital transmission (no "noise")
-High bandwidth - BRI bonded provides 128Kb/s
-Advanced signalling - mutliple addressable devices
-Fast call setup - near instantaneous response

All of these benefits are certainly impressive, but let's get a little closer to home. In fact let's get downright personal. What is ISDN going to do for me and do I need it? Whether you need ISDN or not greatly depends on your communication needs. Please keep in mind that to use ISDN, BOTH ends of the communications link must be using ISDN. If you are considering ISDN for the Internet, be SURE your ISP (Internet Service Provider) handles ISDN connections of your configuration type.

Let us consider two transcriptionists and their communication needs. For brevity, we will call them T1 and T2. T1 does transcription at home from a POTS voice line to a transcription service's digital machine. T1 spends a lot of time on-line listening and transcribing the dictations. Typically, T1 will spend three times the length of the actual dictation on-line, transcribing it. This on-line time is a local call from the phone company. In addition, T1 does tape transcription from minitape transcribers for private clients.

Upon completion, T1 sends the text files to the service company and the other text files to the respective private clients. T1 uses fax for sending and receiving information, and is a light-to-medium user of the Internet. The ISP used by T1 is also a local call. T1 uses a 28.8KB/S POTS modem to send the text files and all transmissions are local calls. All of the communication needs of T1 are currently met by two residential POTS phone lines.

Would T1 benefit from ISDN or save money by using it? No! If you find yourself fitting anywhere close to the above description, don't even think about getting ISDN! Transcribed text files are relatively small. Sending them via a 28.8KB/S modem anywhere is fast and reasonably inexpensive.

Now let's consider T2. T2 has a DVIPS(tm) 16 line Digital Dictation & Transcription system used by several hundred clients. Other transcriptionists access the system and perform the actual transcription on-line. T2 works an overflow relationship with other service bureaus, and sends and receives large voice files via modem and the Internet.

T2 maintains a web page which promotes the service and is constantly sending and receiving large graphics files. T2 is a very heavy Internet user. (Please keep in mind, there are MANY slow data problems on the Internet that will NOT be improved by an ISDN link.) T2 uses real-time, on-line video conferencing to great advantage in the business.

T2 supplies their select clients with the new, digital, solid-state, 23-minute-record-time, hand-held dictation machines. The voice files from these units are transmitted by T2's clients, to the DVIPS(tm) system. T2 also sends voice files to various transcriptionists, some of which are out of the United States, to be transcribed. Currently T2 uses all POTS lines to run the entire operation.

It should be apparent, that T2 would greatly benefit from the reduced transmission times involved in the various processes described above. However, it would take an application specific, detailed cost analysis to show the cost benefits that T2 would obtain from the ISDN service. Quite probably there would be sigificant cost savings.

From the above examples, we can see the distinctions that determine whether ISDN is a viable consideration for you. These are summarized below. If you do a lot of:

1. Large voice file transmissions
2. Large graphics transmissions
3. Video Conferencing
4. A VERY heavy Internet user
5. Send data/files to many long distance recipients

When considering whether ISDN is a cost-viable consideration for you, you must include the capital cost, the installation cost and the operating costs. We regret that we cannot provide this analysis for you, due to the EXTREME variance in costs.

This concludes our four-part series on ISDN. If you have any comments or questions, please feel free to e-mail them to us at We sincerely hope this information has been helpful in your deliberations.

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