PATENT ABSTRACT
A portable terminal having personal computing capability and wireless telecommunications capability. The portable terminal includes a display that is integral with, or otherwise attached to, a display. A housing is rotatably-coupled to the base and/or display. The portable terminal can be closed, wherein the housing overlies the base, or open, wherein base and housing flank the display. The display is fully visible to a user whether the portable terminal is open or closed. When open, a keyboard having keys that are apportioned between the housing and the base is accessible. To accommodate a change in the way in which a user is likely to hold and view the portable terminal when it&#39;s closed versus when it&#39;s open, the image in the display screen is rotated on command, or automatically, when the portable terminal is opened.

PATENT DESCRIPTION
STATEMENT OF RELATED CASES 
     This case claims priority of U.S. Provisional Patent Applications 60/359,199 and 60/359,200, both of which were filed on Feb. 21, 2000 and both of which are incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to wireless telecommunications in general, and, more particularly, to a hand-held processor having wireless communications capabilities. 
     BACKGROUND OF THE INVENTION 
     Hand-held processors, which are commonly called Personal Digital Assistants (“PDAs”), are becoming increasingly popular. PDAs possess relatively limited information processing, storage and retrieval capabilities. With these limited capabilities, a PDA performs specific tasks, such as functioning as an electronic diary, phone book, personal database, memo taker, calculator, alarm clock, etc. A user inputs data directly into a PDA using a stylus or a reduced-size keyboard. Additionally, PDAs are generally capable of exchanging information with a desktop computer, either by a physical connection or an infrared transceiver. PDAs typically include a relatively large display (i.e., large relative to the overall size of the PDA) and several buttons or keys for accessing specific applications and for scrolling to view information. Some PDAs also include a reduced-size keyboard. 
     Lately, wireless telecommunications capabilities have been incorporated into PDAs. Doing so provides advanced functions such as transmitting, receiving and displaying text messages. It also relieves a user of having to transport both a PDA and a wireless terminal (e.g., cellular telephone, pager, etc.). 
     Currently, most of the combined PDA/wireless terminals have one or more shortcomings that relate, among other areas of deficit, to compromised ergonomics or “user-friendliness” relative to a dedicated PDA or a dedicated wireless terminal. For example, some combined PDA/wireless terminals have hinged keyboards that rotate from a closed position to an open position for use. In some of these devices, the telecommunications capabilities can be accessed whether the keyboard is in the open or the closed position. While this arrangement provides a convenience for the user, it causes problems related to the usability of the display and the keys. 
     SUMMARY OF THE INVENTION 
     The present invention is a combined PDA/wireless terminal (hereinafter a “portable terminal”) that avoids some of the shortcomings of combined PDA/wireless terminals in the prior art. 
     A portable terminal in accordance with the illustrative embodiment of the present invention includes a base, a housing, and a display having a display screen. The housing is rotatably-coupled to the base and/or display. The portable terminal can be closed, wherein the housing overlies the base, or open, wherein the housing and the base flank the display. The portable terminal is opened by rotating the housing out-of-plane of the base. The display is fully visible to a user whether the portable terminal is open or closed. 
     The telecommunications capabilities of the portable terminal can be accessed when the portable terminal is closed and when it is open. Most of the PDA capabilities of the portable terminal are accessed when the portable terminal is open, wherein a keyboard having keys that are apportioned between the housing and the base is accessible. 
     When the portable terminal is open, it is typically held by a user in a different orientation than when it is closed. In particular, when closed, the portable terminal is held like a phone (i.e., in a “vertical” orientation) and, when open, it is typically held like an open book (i.e., in a “horizontal” orientation). The display screen is rotated relative to the user as between these two positions. Consequently, if text appears “right-side-up” when the portable terminal is closed, it will appear to a user to be on its side when the portable terminal is open. 
     In accordance with the illustrative embodiment of the present invention, the image in the display screen is rotated 90 degrees when the portable terminal is opened. This rotation re-orients the image so that it is “right-side-up” to a user (when he or she changes the orientation of the portable terminal). The image in the display screen can be electronically rotated, either automatically as the portable terminal is opened or by user command (a keystroke, etc.). In a variation of the illustrative embodiment, the display itself can be physically rotated. 
     In some variations of portable terminal, when the image in display screen is electronically rotated, the functionality of certain soft “convenience” keys that border the screen is also “shifted” or “rotated.” The functionality is shifted so that a key appearing in a certain position relative to the display, from the user&#39;s perspective, always performs the same function. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a block diagram of the salient components of a portable terminal in accordance with the illustrative embodiment of the present invention. 
         FIG. 2  depicts a plan view of a portable terminal in accordance with the illustrative embodiment of the present invention. 
         FIG. 3  depicts a perspective view of the portable terminal shown in FIG.  2 . 
         FIG. 4  depicts the portable terminal of  FIGS. 2 and 3  in an open position wherein its keyboard is accessible. 
         FIGS. 5A-5D  depicts the housing of a portable terminal in accordance with the illustrative embodiment being rotated from a fully closed position to a fully open position. 
         FIG. 6A  depicts a portable terminal when closed, with particular attention to a user&#39;s perspective relative to an image in the display screen. 
         FIG. 6B  depicts a portable terminal when open, with particular attention to a user&#39;s perspective relative to an image in the display screen. 
         FIG. 7A  depicts a portable terminal in accordance with the illustrative embodiment, wherein the portable terminal is open and the image in the display screen has not been electronically rotated. 
         FIG. 7B  depicts the portable terminal of  FIG. 7A  but after electronic rotation of the image in the display screen. 
         FIG. 8A  depicts a portable terminal in accordance with the illustrative embodiment, wherein the portable terminal is open and wherein the display has not been physically rotated. 
         FIG. 8B  depicts the portable terminal of  FIG. 8A  but after physical rotation of the display. 
         FIG. 9A  depicts a portable terminal having four convenience keys that border the corners of the display screen in accordance with the illustrative embodiment. 
         FIG. 9B  depicts the portable terminal of  FIG. 9A  after an image in the display has been electronically rotated and a user has changed his or her viewing perspective. 
         FIG. 10  depicts a block diagram showing electronic rotation of an image in the display screen and rotation of the functionality of convenience keys of a portable terminal in accordance with the illustrative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     This Detailed Description begins with a relatively high-level description of the functionality of various circuitry/components (hereinafter collectively “components”) that compose a portable terminal in accordance with the illustrative embodiment of the present invention. Following this, various physical implementations of some these components, and their mechanical and functional interrelationships with other parts of the portable terminal, are described. 
       FIG. 1  is a high-level block diagram of portable terminal  100  in accordance with the illustrative embodiment of the present invention. Portable terminal  100  provides both wireless telecommunications capabilities and personal computing (i.e., PDA-type) capabilities. 
     With regard to its telecommunications capabilities, portable terminal  100  is capable of transmitting and receiving both voice and data with wireless base stations (not shown) or other wireless terminals, or both. Additionally, portable terminal  100  is capable of supporting telecommunications with wireline terminals through a wireless base station and wireline infrastructure. As to its personal computing capabilities, portable terminal  100  provides typical PDA computing and storage capabilities, including, without limitation, scheduling, address book storage and retrieval, note-taking, and an ability to run a variety of application software packages (e.g., calculators, games, etc.). 
     Portable terminal  100  advantageously includes: control circuitry  102 , transmitter  104 , receiver  106 , antenna  108 , speaker  110 , microphone  112 , display screen  114 , keyboard  116 , additional tactile input devices  118 , infrared transceiver  120 , keyboard-open sensor  122 , environmental sensor(s)  124  and power supply  126 . 
     Control circuitry  102  is advantageously capable of coordinating and controlling the other components of portable terminal  100  to provide, as appropriate, wireless telecommunications capability and personal computing capability, in known fashion. Control circuitry  102  typically includes a processor, memory, and electrical interconnections, among other hardware. In some variations of the illustrative embodiment, a single processor is used for carrying out and controlling PDA operations and wireless telecommunications operations. In some other variations, separate processors are used for PDA operations and wireless telecommunications operations. 
     It will be understood that as used herein, the term “processor” equivalently means a single integrated circuit (“IC”), or a plurality of ICs or other components that are connected, arranged or otherwise grouped together, such as microprocessors, digital signal processors, application-specific integrated circuits, associated memory (e.g., RAM, ROM, etc.) and other ICs and components. Control circuitry  102  can include programmed general-purpose hardware or special-purpose hardware, or both. 
     Transmitter  104  and receiver  106  provide wireless telecommunications capability to portable terminal  100  at radio frequencies. Embodiments of present invention can use any access technology (e.g., frequency-division multiple access, time-division multiple access, time-division duplex, code-division multiple access, etc.) and any modulation scheme (e.g., frequency shift keying, quadrature phase-shift keying, etc.) in accordance with any interface (e.g., IS-41, IS-54, IS-95, GSM, etc.). Furthermore, portable terminal  100  can transmit and receive at any frequency (e.g., 800 MHz, 1800 MHz, etc.). It will be clear to those skilled in the art how to make and use transmitter  104 , receiver  106  and antenna  108 . 
     Speaker  110  is capable of outputting an acoustic signal (e.g., the speech of another person, an alerting or ringing signal, etc.) to a user of portable terminal  100  in well-known fashion. Furthermore, control circuitry  102  is capable of adjusting the volume of the acoustic signal output from speaker  110 . 
     Microphone  112  is capable of receiving an acoustic signal (e.g., the speech of the user of portable terminal  100 , etc.), converting it to an electrical signal containing information that is indicative of the acoustic signal, and of conveying that information to control circuitry  102  for transmission via transmitter  104  in known fashion. 
     Display  114  is a visual display for outputting information (e.g., text, images, video, etc.) to a user of portable terminal  100 . Display  114  includes a display screen, such as a liquid crystal display (“LCD”), and various electronics that, in conjunction with control circuitry  102 , drives the display screen. Display  114  also typically includes a light source (not depicted) for illuminating the display screen. It will be clear to those skilled in the art how to make and use display screen  114 . 
     Keyboard  116  is a tactile input device that includes a set of keys that enables portable terminal  100  to receive information from a user. The keys in keyboard  116  can be used to input a variety of different types of information to portable terminal  100 . For example, the keys of keyboard  116  can be representative of, without limitation, alphabetic characters of an alphabet, numerals, mathematical operators, mathematical functions, specific commands that are useful in conjunction with certain types of application software (e.g., games, etc.), retail items (e.g., food and drink that is offered by a restaurant, specific types of inventory in a warehouse, etc.). 
     Keyboard  116  can include one or more keypads (i.e., regional groupings or grids of numerical and/or function keys arranged for efficient use). Advantageously, keyboard  116  is illuminated by a light source, under the control of control circuitry  102 , to aid the user of portable terminal  100  to enter information into keypad  116 . It will be clear to those skilled in the art how to make and use keyboard  116 . 
     Additional tactile input devices  118  include keys or key-like elements (e.g., a joystick, etc.) that are not physically co-located with the group of keys that define keyboard  116 . These additional keys enable user to deliver information to portable terminal  100 . In some embodiments, the information provided by additional tactile input devices  118  is different than the information that can be provided via the keys in keyboard  116 . For example, one additional tactile input device  118  is a pointing device that moves a cursor in display screen  114 . A second additional tactile input device  118  is a scroll button that allows a user to scroll through menu selections that are presented in display screen  114 . It will be clear to those skilled in the art how to make and use additional tactile input devices  118 . 
     Infrared transceiver  120  is a device (e.g., an IrDA compliant device, etc.) that enables portable terminal  100  to communicate with other devices by modulating infrared light. It will be clear to those skilled in the art how to make and use infrared transceiver  120 . 
     Keyboard-open sensor  122  is a device that senses when keyboard  116 , which in some variations of the illustrative embodiment is rotatable between an open position and a closed position, is in the open position (and/or is being opened). A signal from the keyboard-open sensor is delivered to control circuitry  102 , which, as appropriate, can take certain actions, as described later in this specification. Keyboard-open sensor  122  can be implemented in any of variety ways known to those skilled in the art (e.g., as a mechanical sensor, as an optical sensor, etc.). 
     Environmental sensor(s)  124  are one or more devices that sense ambient environmental factors (e.g., temperature, vibration, noise, light, motion, etc.). Environmental sensor(s)  124  generate a signal that is responsive to the environmental factor, and the generated signal is received by control circuitry  102 . The control circuitry then alters certain aspects of various components (e.g., the level of illumination that is provided to display screen  114  and/or keyboard  116 , the volume of speaker  110 , etc.). 
     It will be appreciated that the specific implementation of environmental sensor(s)  124  is a function of the environmental factor that is being sensed. For example, when environmental sensor  124  is required to sense ambient noise, environmental sensor  124  can be, for example, a microphone, such as microphone  112 . When environmental sensor  124  is required to sense ambient light intensity, it can be, for example, a cadmium-sulfide photoresistor, a charge-coupled device, or other known light-sensitive device. It will be clear to those skilled in the art how to make and use environmental sensors  124 . 
     Power supply  126  supplies electrical power to the components of portable terminal  100  that require power (e.g., processor(s), display screen  114 , sensors  122  and/or  124 , etc.). Power supply  126  is advantageously implemented with rechargeable or replaceable batteries. In some embodiments, at least two separate power supplies  126  are provided. One of the supplies, which is the primary power supply, has greater energy output and storage capacity and is used for powering portable terminal  100  during normal operations. The second supply is a back-up that is used, for example, to maintain data (e.g., address book information, scheduling information, etc.) in memory when the primary power supply is removed (e.g. for replacement, etc.). 
     Various physical implementations of the components that are described (functionally) above, and their mechanical and functional interrelationships with other parts of the portable terminal, are described in applicant&#39;s co-pending patent application Ser. No. 10/161,831 “Portable Terminal With Foldable Keyboard”), which is incorporated herein by reference. Many of the components that are described therein, and which are properly included in at least some versions of the illustrative embodiment of the present invention, are not described herein. The purpose for these omissions is to maintain a focus on elements that are germane to an understanding of the present invention. Also, for the sake of clarity, the components that have been described in terms of their functionality (see FIG.  1 ), are provided with a “call-out” (i.e., numerical identifier) that is in the range  102  through  198 . The illustrative physical implementations these components, some of which appear in  FIGS. 2 through 6D , have been provided with a different call-out. The purpose for this is that, in some cases, a component, as functionally described, incorporates more elements (additionally circuitry, etc.) than is depicted in the illustrative physical implementations. 
     With reference to  FIGS. 2 through 5D , portable terminal  100  includes display  228  and keyboard-housing  230 . Display  228  has a display screen  232  and one or more convenience keys  236  that are advantageously “soft” (i.e., re-definable) keys. Keyboard-housing  230  consists of base  338  and housing  340  (see, FIGS.  3  through  5 D). Housing  340  is rotatably connected to base  338  and/or display  228  at pivot  442 . By virtue of pivot  442 , housing  340  is capable of rotating “out-of-plane” (of base  338 ) about pivot axis  1 — 1 . Pivot axis  1 — 1  bisects display  228 . In the illustrative embodiment, pivot  442  is implemented as rod  444 , and cooperating receiver  446  that depends from housing  340 . 
     In accordance with the illustrative embodiment of the present invention, portable terminal  100  can be used in either of two basic configurations: “closed,” as depicted in  FIGS. 2 ,  3 , and  5 A or “open,” as depicted in  FIGS. 4 and 5D . 
     When portable terminal  100  is closed, housing  340  is superposed over base  338  so that the two housings coincide and serve as a handle for gripping the portable terminal  100  in the manner of a conventional wireless phone. Additionally, in this state, base  338  and housing  340  serve as a cover for a keyboard. As described further below, the keyboard is partitioned into two portions, one disposed on the inner surface of the base and the other on the inner surface of the housing. When closed, portable terminal  100  can be used to make and receive telephone calls. 
     To use various PDA-type applications (e.g., address book, schedule, etc.) of portable terminal  100  or to enter alphanumeric data (e.g., to send a data message, etc.), the keyboard of portable terminal  100  is accessed. To do so, portable terminal  100  is opened by rotating housing  340  out-of-plane away from base  338 , as illustrated in  FIGS. 5B and 5C . 
     In the illustrative embodiment, the keyboard is implemented in two portions, keyboard portion  548  and keyboard portion  550 . Keyboard portion  548  is disposed within base  338  and keyboard portion  550  is disposed within housing  340 . When portable terminal  100  is open, display  228  is disposed between keyboard portion  548  and keyboard portion  550 . 
     In the illustrative embodiment, housing  340  is rotated 180 degrees out-of-plane to a “fully-open” position. It will be understood, however, that housing  340  need not be rotated a full 180 degrees to access and use the keyboard. In fact, a user might prefer to rotate housing  340  somewhat less than 180 degrees (e.g., 160 degrees rotation, etc.). In particular, some users might find that when base  338  and housing  340  are less than 180 degrees apart, less stress is placed on their wrists, especially during periods of extended use (e.g., game playing, etc.). Alternatively, in some variations of portable terminal  100 , housing  340  is rotatable beyond 180 degrees, again for the comfort of the user. 
     As suggested above, when portable terminal  100  is closed, it is most likely to be used in the manner of a conventional wireless terminal to send and receive calls.  FIG. 6A  depicts portable terminal  100  (keyboard housing  230  shown in phantom) closed. From the perspective of a user that is holding “closed” portable terminal  100  in front of himself or herself, N(orth) is “up,” S(outh) is “down,” E(ast) is “right,” and W(est) is “left,” (this is the same view that is presented to the reader, as he or she gazes at FIG.  6 A). So, to the user, the word “CLOSED,” which appears in display screen  232 , is properly oriented for reading. 
     As previously indicated, when it is open, portable terminal  100  is most likely being used as a PDA.  FIG. 6B  depicts portable terminal  100  (base  338  and housing  340  shown in phantom). From the perspective of a user that is holding “open” portable terminal  100  in front of himself or herself, N(orth) is “right,” S(outh) is “left,” E(ast) is “down,” and W(est) is “up.” This is the view that is presented to the reader when he or she rotates  FIG. 6B  clockwise by 90 degrees. So, to the user, the word “OPEN,” which appears in display screen  232 , is not properly oriented for reading. (A user could use portable terminal  100  in the manner of a “flip-phone” [i.e., in a vertical orientation] when it is open, so that the word “OPEN” would be properly oriented for reading. But this would make it very difficult to use the keyboard, in particular the alpha-character keys.) 
     Consequently, in accordance with the illustrative embodiment of the present invention, the image in display screen  232  is rotated counterclockwise 90 degrees. For a user that is holding portable terminal  100  in a “horizontal” orientation (i.e., housing  340  to the right of display  228  and base  338  to the left of display  228 ), this re-orients the image so that it is in a “normal” reading orientation. This horizontal orientation is assumed to be the user&#39;s orientation for the description of  FIGS. 7A ,  7 B and  8 A and  8 B, below. Consequently, these Figures should be viewed as indicated by the arrows that appear in those Figures. 
     Rotation can be accomplished in at least two ways. One way is to electronically rotate the image. Electronic rotation is described with reference to  FIGS. 7A ,  7 B and  10 .  FIG. 7A  depicts open portable terminal  100  before the image in display screen  232  is electronically rotated. In  FIG. 7A , screen image N(orth) is “right,” and screen image W(est) is “up,” etc. To a user, the word “OPEN,” which appears in display screen  232 , is not properly oriented. 
       FIG. 7B  depicts open portable terminal  100  after the image in display screen  232  is electronically rotated. In  FIG. 7B , screen image N(orth) is “up,” screen image W(est) is “left,” etc. To a user, the word “OPEN,” which appears in display screen  232 , is now properly oriented. 
     Portable terminal  100  is advantageously capable of automatically (i.e., in the absence of an explicit command from the user) electronically rotating the image in display screen  232  and also capable of electronically rotating the image on command from the user. In accordance with the illustrative embodiment of the invention, automatic rotation is triggered as a user rotates housing  340  away from base  338  to open portable terminal  100 . More particularly, when keyboard open sensor  122  senses that the portable terminal  100  is being opened, it sends a signal to control circuitry  102 . When the signal is received by control circuitry  102 , image-rotating processing rotates the image in display screen  232 . It is within the capabilities of those skilled in the art to electronically rotate an image, so implementation details are not described here. 
     Alternatively, a user can cause an image in display screen  232  to electronically rotate by explicit command. That is, the user can rotate the image by depressing a key. This key can be, without limitation, a key in keyboard portion  548  or keyboard portion  550  or one of convenience keys  236 . 
       FIG. 10  depicts a high-level block diagram that illustrates, among other functions, electronic image rotation, as described above and performed by control circuitry  102 . As depicted in  FIG. 10 , an image is generated in operation  962 . In operation  964 , the image is rotated (e.g., counterclockwise by 90 degrees, etc.) if user-generated rotate command  966  is issued (e.g., a user depressing a key, etc.) or if automatic rotate command  968  is issued (e.g., from keyboard open sensor  122 , etc.). To rotate the image 90 degrees counterclockwise, the image is transformed as follows:
 ( x,y )→(− y,x )  [1]         where: x and y are the coordinates in a two-dimensional Cartesian coordinate system.
 
Operations  962 ,  964 ,  966 , and  968  can be performed by hardware, software, or a combination of both. When portable terminal  100  is closed (after having been open) such that keyboard-open sensor  122  no longer senses an “open” condition, image rotation ceases. Alternatively, a keystroke by a user can cause the image rotation to stop.
       
     A second way to rotate the image is to physically rotate display  228  (or display screen  232 ). Physical rotation is illustrated with reference to  FIGS. 8A and 8B .  FIG. 8A  depicts open portable terminal  100  before display  228  is rotated (e.g., by hand, etc.). In  FIG. 8A , screen image N(orth) is “right,” and screen image W(est) is “up,” etc. To a user, the word “OPEN,” which appears in display screen  232 , is not properly oriented. 
     It will be appreciated that portable terminal  100  must be specifically configured or adapted to enable display  228  to rotate independently of housing  340  and base  338 . Representative of such an adaptation is an arrangement consisting of ball  858  and two hemispherical detents  860 A and  860 B. When ball  858  engages detent  860 A, display  228  locks in place with the orientation depicted in FIG.  8 A. With turning force, ball  858  disengages from detent  860 A and display  228  is free to rotate. With continued rotation, ball  858  engages detent  860 B, such that display  228  is locked in place with the orientation depicted in FIG.  8 B. In  FIG. 8B , screen image N(orth) is “up,” screen image W(est) is “left,” etc. To a user holding portable terminal  100  in a horizontal position (as described above), the word “OPEN,” which appears in display screen  232 , is now properly oriented. A variety of other arrangements, as are well known to those skilled in the art, that enable display  228  to rotate independently of housing  340  and base  338  can suitably be used in other variations of the illustrative embodiment. 
     In some variations of portable terminal  100 , display  228  includes four convenience keys  236 . For example, in  FIGS. 9A and 9B , which show display  228  without housing  340  and base  338 , display  228  includes convenience keys  236 - 1 ,  236 - 2 ,  236 - 3 , and  236 - 4  bordering the corners of display screen  232 . In variations of the portable terminal  100  in which the image in display screen  232  (but not display  228 ) is rotated (i.e., electronic image rotation), the spatial orientation of convenience keys  236 - 1 ,  236 - 2 ,  236 - 3 , and  236 - 4  changes, relative to the image, upon such rotation. This scenario is illustrated by  FIGS. 9A and 9B . 
     In  FIG. 9A , portable terminal  100  is closed, and a user views display screen  232  as indicated by the arrows. Consequently, the user sees convenience key  236 - 1  bordering the upper left of display screen  232  and convenience key  236 - 2  bordering the lower left of display screen  232 , etc. Assume that the user opens portable terminal  100 . And, in conjunction with this, assume that the image in display  232  is electronically rotated as described above and the user repositions portable terminal  100  such that it is being held in a horizontal position and viewed as shown by the arrows in FIG.  9 B. 
     From the user&#39;s perspective, convenience key  236 - 1  no longer borders the upper left of display screen  232  and convenience key  236 - 2  no longer borders the lower left of display screen  232 . As can be seen from  FIG. 9B , the user sees convenience key  236 - 1  bordering the upper right of display  232  and convenience key  236 - 2  bordering the upper left of display screen  232 . 
     If the various convenience keys perform different functions, this change in spatial orientation might be problematic for a user. In particular, with continued use, a user will tend to associate the function of a first convenience key with its position relative to the screen (e.g., the key to the lower-left of the screen accesses a telephone directory, etc.). But when the image is electronically rotated, and the user changes his or her perspective relative to portable terminal  100 , a second convenience key is, from the user&#39;s perspective, now in the position that was occupied by the first convenience key. Consequently, to the extent that a user associates the function of a key with its position relative to display screen  232 , he or she must recognize that the function will change depending upon whether portable terminal  100  is open or closed. This is undesirable. 
     In accordance with some variations of portable terminal  100 , when the image in display screen  232  is electronically rotated, the functionality of convenience keys  236  is “shifted” or “rotated” accordingly so that a key appearing in a certain position relative to the display, from the user&#39;s perspective, always performs the same function. So, for example, the convenience key that appears, from a user&#39;s perspective, at the lower left of the display always accesses the telephone directory, etc. For the scenario illustrated in  FIGS. 9A and 9B , the functionality of each convenience key should be “shifted” to the convenience key that next appears with counterclockwise rotation. That is, the functionality of convenience key  236 - 1  is shifted to convenience key  236 - 2 , the functionality of convenience key  236 - 2  is shifted to convenience key  236 - 3 , etc. To this end, convenience keys  236  are advantageously software re-definable (i.e., soft) keys. 
     It will be understood that the terms “shifted” or “rotated,” as used to describe the change in function of convenience keys  236 , is intended to be descriptive of the end result rather than the process itself. That is; the functionality of one key is not actually shifted to another; rather, the operation of the keys are simply redefined or reprogrammed by the circuitry/software of portable terminal  100  in known fashion. This is the sense in which the terms “shifted” or “rotated” are used in this description and the appended claims with regard to convenience keys  236 . 
       FIG. 10  depicts a high-level block diagram of method  900  for operating portable terminal  100 . The method pertains to rotation of an image and shifting of convenience-key functionality, as described above and performed by control circuitry  102 . 
     As depicted in  FIG. 10 , in operation  970 , the functionality of convenience keys  962  is rotated (e.g., counterclockwise by 90 degrees, etc.) if user-generated rotate command  966  is issued (e.g., a user depressing a key, etc.) or if automatic rotate command  968  is issued (e.g., from keyboard open sensor  122 , etc.). Operations  966 ,  968 , and  970  can be performed by hardware, software, or a combination of both. When portable terminal  100  is closed (after having been open) such that keyboard-open sensor  122  no longer senses an “open” condition, rotation of image or shifting of convenience-key functionality ceases. Alternatively, a keystroke by a user can cause the rotation and shifting to stop. 
     It is to be understood that the above-described embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by those skilled in the art without departing from the scope of the invention. It is therefore intended that such variations be included within the scope of the following claims and their equivalents.