BUSINESS TEXT-MESSAGING USING A STANDARD CELLULAR KEYPAD
- Telecom Addressing
- The present multi-tap
protocol is suitable for short innocuous messages but for serious
business messaging it is slow and inadequate. Although data-based
search protocols are now included with most cellular phones they
are designed for selecting and correcting recurrent words in
simple messages. They are in adequate for simple business correspondence
which generally involve punctuation and special symbols.
- Because text-messaging
is the fastest growing market in cellular phone usage, but one
that totally neglects business text-messaging, a proprietary
software protocol for serious text-messaging has been
developed that employs a standard cellular phone keypad and permits
unambiguous alphanumeric data input. This unique procedure denoted
the Input Doublet Protocol allows rapid letter, number, punctuation
and special symbol inputs as readily as would a full keyboard.
The Input Doublet Protocol provides a fixed number of keystrokes
per character and greater speed and convenience for text messaging.
- This text-messaging
protocol is compared in specifics with the conventional multi-tap
protocol in common usage, particularly keystrokes required per
character. There are no timing delays involved with the Input
Doublet Protocol. Characters are displayed as rapidly as they
- For example, consider
the following text-message sent from a field salesman to the
home-office computer or office manager using a standard cellular
- While both the
multi-tap and Input Doublet Protocols would display exactly the
same message multi-tap would require a user with extraordinary
patience to endure the timing-delay requirements of this poorly
conceived procedure totally unsuitable for serious business messaging
with its susceptibility to timing errors. In contrast the Input
Doublet Protocol would accommodate this business message as rapidly
as the characters are keyed in.
- The Input Doublet
Protocol is described in detail below.
- A. BACKGROUND
- B. INPUT DOUBLET PROTOCOL
- C. SPECIAL
- D. ANALYSIS
- E. DISCUSSION
- F. CONCLUSION
- A. BACKGROUND
- Text messaging using the
standard cellular keypad accounts for the most rapid growth of
cellular phone usage. Yet text messaging using the standard multi-tap
cellular keypad is a tedious process that is best avoided for
serious cellular phone users. Not only do the number of keystokes
differ for each letter depending on their position on each key.
- Not only is their is no
cadence established because the number of keystrokes differ but
access to punctuation breaks the messaging stride. Hence there
is no learning curve and a veteran text messaging user is only
marginally faster in composing a message than a neophyte.
- Moreover if the number
of keystrokes per letter is delayed this timing error causes
the wrong character to be displayed. For example to input the
- by multi-tap requires
that the 2 key be actuated six times: three times for the letter
C, once for the letter A and twice for the letter B. Accordingly
- must be entered with the
proper delay between groups, and this is a typical example. If
the time delay between keystrokes is too short or keying rate
too slow only nonsense results.
- These timing errors are
among the major drawbacks to multi-tap, even with data-based
search protocols. The time delay can be almost as long as a second,
followed by a beep, a difficulty in business text-messaging,
partuclerly with its need for punctuation and special symbols.
Consequently multi-tap is so time-consuming that special abbreviations
are available to speed up messaging, requiring a data-base.
- While there are available
in the market dedicated text messaging devices using a full keyboard
these are inconvenient for ordinary usage, expensive and generally
bulkier than ordinary cellular phones. Their usage is restricted
to those engaged in intense text messaging.
- Considering conventional
cellular phones, the evaluation of text-messaging protocols largely
involves the establishment of a paradigm upon which their characteristics
can be compared. The four principal criteria are as follows:
- the number of characters
per second (CPS),
- the specific number of
keystrokes per character (KSPC),
- the learning rate, and
- the adaptability to the
conventional cellular phone configuration.
- The first criteria measures
typing rate, though reasonably quantitative, it is still depends
highly on degree of skill.
- The second criteria (KSPC)
is an average over a message and measures the gross efficiency
of data input (MacKenzie,
2002). The KSPC his
been most widely studied and the easiest criteria to quantize
- The third criteria would
depend on establishing a typing cadence, which would be easiest
with the same specific KSPC for each of the characters.
- The fourth criteria is
the principal limitation on input protocols: practicality. Some
approaches will probably not prove commercially acceptable to
established firms, such as requiring more than a single key to
be depressed simultaneously, requiring high degree of ambidexterity,
quite difficult while multi-tasking; or requiring a special key
to differentiate between characters or the use of a stylus.
- Most of the protocols
being currently considered by those in the field of phone-human
text-messaging interactions are compared below.
- With few exceptions these
protocols require either a fundamental change in the usual cellular
phone configuration or would require a dictionary or data-base
to speed up the text-messaging process. The problem with timing
error is that a subsequent keystroke, struck too soon, causes
an error in the message, slowing the CPS.
- Consider now an advanced
text messaging protocol using a standard cellular keypad and
a fixed specific KSPC for all characters., thereby establishing
a cadence and permitting a learning curve without requiring a dictionary or data-base to speed
up the text-messaging process.
- B. INPUT DOUBLET
This proprietary approach to text messaging denoted the Input
Doublet Protocol (IDP) is a software solution using the standard
cellular keypad, allowing the user a comfortable transition to
IDP. The IDP neither requires different numbers of keystrokes
for each letter, nor is it susceptible to timing errors. Because
IDP is not menu driven no dictionary or database is required.
- The closest approach to
IDP is Two-Key described above. Two-Key was originally considered
promising because it permitted a fixed KSPC (Butts
& Cockburn) ,
similarly to IDP but Two-Key cannot accommodate special symbols.
- According to the IDP two
keystrokes alone are required for each character whether letter,
number, or punctuation (KSPC=2) to create a unique identifier:position
doublet as shown below. The KSPC is essentially constant for
all characters, allowing a cadence to be established to attain
a higher CPS.
- The identifier-position
doublet is the basic unit of the IDP. The standard cellular phone
uses twelve keys to specify the desired characters. The doublets
permit the cellular keypad shown below to emulate a full keyboard.
Each doublet specifies a single letter, number or symbol.
- For example character
a is located on key 2 in sequence position 1 as shown above.
It is specified simply as doublet a1.
- Character c is likewise
located on key 2 but in sequence position 3. Hence it is specified
simply as doublet c3.
- Similarly n is located
on key 6 in sequence position 2. Hence it is specified simply
as doublet n2.
- Using this protocol with
just two keystrokes letter q can be identified as doublet q2
- and z as doublet z4.
- The actuation sequence
for the doublets is shown in below.
- The most important feature
of the IDP is that the same number of keystrokes are required
for each letter: a doublet allowing a rapid cadence to be established.
Equally important, the sequence positions follows from the letters
chosen. Thus 3 always follows c, 2 always follows n, 2 always
follows q and 4 always follows z. Hence, the letters are mnemonics
leading to the sequence positions. Accordingly, when key stroking
the letter c is recalled as c3.
- Hence a learning curve
- C. SPECIAL
- There are four identifier
keys available not associated with keypad letters: '0', '1',
'*' and '#'. Because there are twelve possible position keys,
therefore 48 separate doublets are available to the IDP.
- Using '0' key as the identifier
the IDP can readily accommodate numerals.
- For punctuation the '#'
and the '1' keys can be used as identifiers.
- Of course these doublets
would ostensibly require memorization and therefore would be
less often used, if at all, and probably of no consequence to
most users. They would be important however for business and
technical text messaging.
- When used as doublets
the identifier keys can act as function keys as shown.
- For example, inputting
## displays all of the punctuation marks but with a significant
difference than is now practiced using multi-tap. At present
the punctuation marks are displayed and by scrolling the required
mark is chosen, a procedure that is time consuming and interrupts
the text messaging procedure and cadence. The #* doublet would
display special keys such as ¥ or £ and other monetary
symbols which are important for international business transactions
for rapid unambiguous transmission, for example, of stock or
commodity prices using a standard cellular phone.
- With the IDP the associated
doublet is displayed with each punctuation mark, which can then
be directly entered. Hence, actuating the doublet ## or #* could
display punctuation or special symbols. Evidently with usage
the most common symbols would be recalled without the display.
Again there is a distinct learning curve established.
- For example the number
$86,400 has seven characters, two of which are special symbol:
'$' and ','. This would require the seven doublets 14 08 06 #2 04 00 00.
The number 3.1416 has six characters and would require the six
doublets 03 #3 01 04 01 06.
- D. ANALYSIS
- To compare the IDP with
the conventional text-messaging protocol a sample message will
message comprises 111 alphanumeric characters; 3 punctuation
marks; 3 special symbols; and 21 spaces, all of which must be
keyed in and displayed.
the conventional multi-tap text-messaging protocol the required
keystrokes are as follows:
- Scrolling is required
for special symbols. For this conventional multi-tap message
the IDP the required keystrokes are as follows:
- For this IDP message KSPC=2.00.
- The KSPC for the IDP is
almost 15% more efficient than the multi-tap protocol. Moreover
scrolling time is not counted with the conventional protocol,
which would significantly decrease the multi-tap CPS count.
- E. DISCUSSION
- The IDP as described herein
is superior in terms of convenience in learning and usage compared
to other proposed approaches. The IDP requires no more than reprogramming
text messaging mode of standard cellular phones. Accordingly,
- incorporates a fixed KSPC
to permit a cadence to be established,
- uses the cadence to promote
a rapid CPS,
- readily allows input of
punctuation and symbols,
- has no timing delays,
- allows a learning curve
to be established,
- uses the conventional
cellular phone configuration, and
- does not require a dictionary
- F. CONCLUSION
- The IDP is a very powerful
proprietary means of using the telephone keypad for alphanumeric
data input by emulating a full keyboard by use of doublets, eliminating
the possibility of timing errors. The IDP would be comfortably
used by present multi-tap users and can be programmed as a switchable
option on cellular phones in text messaging mode. It is the serious
users who would most appreciate the convenience of the IDP.
- G. REFERENCES
MacKenzie, I. S., &
Soukoreff, R. W. (2002). Text entry for mobile computing: Models
and methods, theory and practice. Human-Computer Interaction,
17, p 147
Butts L. & Cockburn
A. (2005) Human-Computer interaction Lab. Canterbury University.
Wigdor D. & Balakrishnan
(2003) Using tilt for text input to mobile phones, Proc. UIST,
Dunlop, M. D. & Crossan,
A. (2000), Predictive entry methods for mobile phones, Personal
Technologies p. 134
ISO/IEC 9995-8 (1994) Information
systems. Keyboard layouts for text and office systems (Part 8).
James, C. L. & Reischel,
K. M. (2001), Text input for mobile devices: comparing model prediction
to actual performance, Proc. of CHI2001, ACM, New York, p365
Silfverberg, M., MacKenzie,
I. S. & Korhonen, P. (2000), Predicting text entry speed on
Proc of CHI2000, ACM, New York,p 9
- Moishe Garfinkle,
- Telecom Addressing
- (215) 235-5042