Patent Publication Number: US-7591657-B2

Title: Reversible universal serial bus (USB) connector

Description:
This application is a continuation of U.S. patent application Ser. No. 11/491,284 filed Jul. 24, 2006, now U.S. Pat. No. 7,363,947 which is a continuation of U.S. patent application Ser. No. 11/185,771 filed Jul. 21, 2005, now issued as U.S. Pat. No. 7,094,086, which in turn claims the benefit of U.S. Provisional Patent Application No. 60/592,517 filed Aug. 2, 2004. 

   FIELD AND BACKGROUND OF THE INVENTION 
   The present invention relates to Universal Serial Bus (USB) devices, and, in particular, it concerns USB devices for reversible coupling with USB hosts. The invention further relates to reversible USB connectors. 
   By way of introduction, a standard USB plug can only be inserted into a standard USB receptacle in one of two possible orientations. Therefore, if the USB plug is orientated incorrectly in relation to the USB receptacle, the plug and receptacle cannot be coupled. As there is no standard for the positioning of a USB receptacle on a device, the user will often attempt to insert the plug into a receptacle in an incorrect orientation. In a situation in which a USB plug is frequently inserted and removed from a USB receptacle, such errors may become a significant inconvenience for the user. Also, many USB devices have a USB plug which extends directly from the body of the USB device. When such a USB device is connected to a USB receptacle of a host appliance that has another port, the USB device frequently blocks access to the other port of the host and prevents other USB devices from being connected to the host appliance. Where the body of the USB device is asymmetric, i.e., the USB plug is positioned asymmetrically in relation to the sides of the USB device, insertion in a first orientation may block the neighboring port, whereas if it were possible to insert the device in an inverted orientation the insertion would not block the neighboring port. Also, in the case of a USB device that has an asymmetric body, insertion in a first orientation may not be possible due to the combined structure of the device and the host appliance, whereas if it were possible to insert the device in a different orientation the insertion could become possible. 
   Of relevance to the present invention is U.S. Pat. No. 6,394,813 to Stout, et al. Stout, et al. teaches a USB connector adapter connected to a peripheral device. The adapter is adjustable so as to allow selective reorientation of the peripheral device with respect to a host device. A shortcoming of the aforementioned system is due the need of ensuring that the adapter is always inserted into the USB connector of the host device in the same orientation. 
   Also of relevance to the present invention is U.S. Pat. No. 6,733,329 to Yang. Yang teaches a interchangeable USB adapter connected to a peripheral device. The USB adapter is configured for being interchangeable between an A-type USB connector, a B-type USB connector and a mini type USB connector A shortcoming of the aforementioned system is due the need of ensuring that the adapter is always inserted into the USB connector of the host device in the same orientation. A further shortcoming of the aforementioned system is that the peripheral device has to have the same orientation with respect to the host device when connected therewith. 
   Also of relevance to the present invention is U.S. Publication No. 2003/0171035 to Yoo. Yoo teaches a USB peripheral device having a printed circuit board having electrical terminals on both sides of the printed circuit board. Yoo also teaches an adapter having a standard USB plug at one end and a slit at the other end having terminals thereon. The USB peripheral device is then connected to the adapter by inserting the printed circuit board into the slit of the adapter. The printed circuit board can be inserted into the slit in two orientations. A shortcoming of the aforementioned system is due the need of ensuring that the adapter is always inserted into the USB connector of the host device in the same orientation. An additional shortcoming of the aforementioned system is that the system is not convenient to use. A further shortcoming of the aforementioned system is that the printed circuit board needs to be specially designed to incorporate the reversibility feature. 
   There is therefore a need for a reliable, easy-to-use and reversible USB plug that can be connected to a standard USB receptacle in two orientations without having to adjust the plug prior to, during or after connection. Additionally, there is a need for a reliable, easy-to-use and reversible USB receptacle that can be connected to a standard USB plug in two orientations without having to adjust the plug prior to, during or after connection. Furthermore, there is a need for a reversible device for connecting in two orientations to an appliance which includes a standard USB receptacle without having to adjust the device prior to, during or after connection. 
   SUMMARY OF THE INVENTION 
   The present invention is a reversible USB device and a corresponding connector construction. 
   According to the teachings of the present invention there is provided, a reversible connector for coupling with a USB A-type standard connector, the standard connector having a hollow section, a fixed set of four electrical contacts disposed on one side of the hollow section and an electrically conducting shield disposed on three sides of the hollow section, the reversible connector comprising: a sleeve, configured for cooperating with the electrically conducting shield; a tongue arrangement centrally disposed in the sleeve, the tongue arrangement including a first set of four electrical contact regions on a first side of the tongue arrangement and a second set of four electrical contact regions on a second side of the tongue arrangement, the tongue arrangement being configured such that: (a) in a first coupling orientation of the reversible connector with the standard connector, the tongue arrangement is moved in a first direction by the standard connector and the first set of electrical contact regions is mechanically connected with the set of electrical contacts of the standard connector; and (b) in a second coupling orientation of the reversible connector with the standard connector, the tongue arrangement is moved in a second direction by the standard connector and the second set of electrical contact regions is mechanically connected with the set of electrical contacts of the standard connector; and a centering mechanism configured for maintaining the tongue arrangement centrally within the sleeve prior to the tongue arrangement and the standard connector making contact. 
   According to a further feature of the present invention, the centering mechanism is further configured such that initial contact of the centering mechanism with the standard connector releases the centering mechanism, thereby allowing movement of the tongue arrangement. 
   According to a further feature of the present invention, the centering mechanism includes a spring recoiled sliding locking mechanism. 
   According to a further feature of the present invention, there is also provided a contact raising arrangement configured for: (a) deflecting the first set of contact regions in the first coupling orientation so that the first set of contact regions makes mechanical contact with the set of electrical contacts of the standard connector; and (b) deflecting the second set of contact regions in the second coupling orientation so that the second set of contact regions makes mechanical contact with the set of electrical contacts of the standard connector. 
   According to a further feature of the present invention, the tongue arrangement includes a central insulating layer electrically isolating the first set of electrical contact regions from the second set of electrical contact regions. 
   According to a further feature of the present invention, the central insulating layer includes a plurality of grooves, the first set of electrical contact regions and the second set of electrical contact regions being recessed in the grooves. 
   According to a further feature of the present invention, the central insulating layer is substantially rigid. 
   According to a further feature of the present invention, the reversible connector is a receptacle and the standard connector is a USB A-type plug. 
   There is also provided according to the teachings of the present invention, a reversible USB appliance for receiving in two orientations a device having a standard USB A-type plug, the USB appliance comprising: (a) a functional unit; (b) a body containing the functional unit; and (c) the aforementioned reversible receptacle non-rotatably coupled to the body for operationally coupling with the USB A-type standard plug in the two coupling orientations. 
   According to a further feature of the present invention, the reversible connector is a plug and the standard connector is a USB A-type receptacle. 
   There is also provided according to the teachings of the present invention, a reversible USB device for engaging in two orientations with an appliance, the appliance having a standard USB A-type receptacle, the USB device comprising: (a) a functional unit; (b) a body containing the functional unit; and (c) the aforementioned reversible plug non-rotatably coupled so as to protrude from the body, the reversible plug adapted for operationally coupling with the standard USB A-type receptacle in the two coupling orientations. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: 
       FIG. 1   a  is an isometric view of a reversible plug that is constructed and operable in accordance with a preferred embodiment of the present invention; 
       FIG. 1   b  is a plan view of the plug of  FIG. 1   a;    
       FIG. 1   c  is a sectional view through the line C-C of  FIG. 1   b;    
       FIG. 1   d  is an exploded isometric view of the plug of  FIG. 1   a;    
       FIG. 1   e  is an isometric view of the plug of  FIG. 1   a  (having its outer housing removed for clarity) making contact with an A-type USB standard receptacle (also having its outer housing removed for clarity); 
       FIG. 1   f  is a schematic semi-transparent side view of the plug and receptacle of  FIG. 1   e;    
       FIG. 2   a  is an isometric view of a reversible plug that is constructed and operable in accordance with a first alternate embodiment of the present invention; 
       FIG. 2   b  is a front view of the plug of  FIG. 2   a;    
       FIG. 2   c  is a sectional view through the line C-C of  FIG. 2   b;    
       FIG. 2   d  is a sectional view of the plug of  FIG. 2   a  making contact with an A-type USB standard receptacle; 
       FIG. 2   e  is a sectional view of the plug and receptacle of  FIG. 2   d  fully coupled; 
       FIG. 2   f  is an isometric view of the plug and receptacle of  FIG. 2   e  fully coupled (having their outer housing removed for clarity); 
       FIG. 2   g  is a schematic view of an electronic switching arrangement for use with the plug of  FIG. 2   a;    
       FIG. 2   h  is a sectional view of a reversible plug, that is constructed and operable in accordance with a second alternate embodiment of the present invention, making contact with an A-type USB standard receptacle; 
       FIG. 2   i  is a sectional view of the plug and receptacle of  FIG. 2   h  fully coupled; 
       FIG. 2   j  is an isometric view of the plug and receptacle of  FIG. 2   h  fully coupled (having their outer housing removed for clarity); 
       FIG. 2   k  is a top view of a tongue arrangement of the plug of  FIG. 2   h;    
       FIG. 2   m  is an isometric view of the tongue arrangement of  FIG. 2   k;    
       FIG. 3   a  is an isometric view of a reversible plug that is constructed and operable in accordance with a third alternate embodiment of the present invention; 
       FIG. 3   b  is a plan view of the plug of  FIG. 3   a;    
       FIG. 3   c  is a sectional view through line C-C of  FIG. 3   b;    
       FIG. 3   d  is a sectional view through line D-D of  FIG. 3   b;    
       FIG. 3   e  is a plan view of the plug of  FIG. 3   a  inserted into an A-type USB standard receptacle; 
       FIG. 3   f  is a sectional view through the line F-F of  FIG. 3   e;    
       FIG. 4   a  is an isometric view of a reversible plug that is constructed and operable in accordance with a fourth alternate embodiment of the present invention; 
       FIG. 4   b  is a plan view of the plug of  FIG. 4   a;    
       FIG. 4   c  is a sectional view through line C-C of  FIG. 4   b;    
       FIG. 4   d  is a sectional view through line D-D of  FIG. 4   c;    
       FIG. 4   e  is an exploded view of the plug of  FIG. 4   a;    
       FIG. 4   f  is a plan view of the plug of  FIG. 4   a  inserted into an A-type USB standard receptacle; 
       FIG. 4   g  is a sectional view through line G-G of  FIG. 4   f;    
       FIG. 5   a  is an isometric view of a reversible receptacle that is constructed and operable in accordance with a preferred embodiment of the present invention; 
       FIG. 5   b  is an exploded isometric view of the receptacle of  FIG. 5   a;    
       FIG. 5   c  is a plan view of the receptacle of  FIG. 5   a  making contact with an A-type USB standard plug; 
       FIG. 5   d  is a sectional view through line D-D of  FIG. 5   c;    
       FIG. 5   e  is a sectional view of the receptacle and plug of  FIG. 5   c  fully coupled; 
       FIG. 6   a  is an isometric view of a reversible receptacle (without its accompanying circuit board) that is constructed and operable in accordance with a first alternate embodiment of the present invention; 
       FIG. 6   b  is a plan view of the receptacle of  FIG. 6   a  (with its accompanying circuit board); 
       FIG. 6   c  is an exploded isometric view of the receptacle of  FIG. 6   c;    
       FIG. 6   d  is a sectional of the receptacle of  FIG. 6   b  through line D-D making contact with an A-type USB standard plug; 
       FIG. 6   e  is a sectional view of the plug and receptacle of  FIG. 6   d , fully coupled; 
       FIG. 6   f  is a sectional view of a reversible receptacle that is constructed and operable in accordance with a second alternate embodiment of the present invention; 
       FIG. 6   g  is an exploded isometric view of the receptacle of  FIG. 6   f;    
       FIG. 6   h  is a rear isometric view of a tongue arrangement of the receptacle of  FIG. 6   f;    
       FIG. 6   i  is a front isometric view of the tongue arrangement of  FIG. 6   h;    
       FIG. 7   a  is an isometric view of a reversible receptacle that is constructed and operable in accordance with a third alternate embodiment of the present invention; 
       FIG. 7   b  is a plan view of the receptacle of  FIG. 7   a;    
       FIG. 7   c  is a sectional view through line C-C of  FIG. 7   b;    
       FIG. 7   d  is a sectional view of the receptacle of  FIG. 7   c  coupled with an A-type USB standard plug; 
       FIG. 8   a  is an isometric view of a reversible receptacle that is constructed and operable in accordance with a fourth alternate embodiment of the present invention; 
       FIG. 8   b  is an exploded isometric view of the receptacle of  FIG. 8   a;    
       FIG. 8   c  is an exploded isometric view of the lower block of the receptacle of  FIG. 8   b;    
       FIG. 8   d  is a plan view of the receptacle of  FIG. 8   a  making contact with an A-type USB standard plug; 
       FIG. 8   e  is a sectional view through line E-E of  FIG. 8   d;    
       FIG. 8   f  is a sectional view of the receptacle and plug of  FIG. 8   d , fully coupled; and 
       FIG. 8   g  is an isometric view of the receptacle of  FIG. 8   f  (having its shield removed for clarity) when fully coupled with the plug of  FIG. 8   f , the plug being removed for clarity; 
       FIGS. 9   a - 9   h  are generic schematic representations of a reversible device that is constructed and operable in accordance with a preferred embodiment of the present invention; 
       FIG. 10  is a generic schematic representation of an appliance which incorporates a reversible receptacle that is constructed in accordance with a preferred embodiment of the current invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention is a reversible USB connector construction and method of operation thereof. 
   The principles and operation of a reversible USB connector according to the present invention may be better understood with reference to the drawings and the accompanying description. 
   By way of introduction, the present invention teaches a reversible USB connector for connection with a standard A-type USB connector. The reversible connector is configured for engagement with the standard connector interchangeably in each of two orientations. Thus the reversible connector can mate with the standard connector in a first orientation, the connectors can be disconnected, one of the connectors can be rotated through 180 degrees and the connectors can then mate again without having to reconfigure or otherwise adjust the reversible connector. The term “connector” is defined herein to include both plugs and receptacles. An A-type USB standard connector is defined herein as a connector which conforms to USB standards without any modification to render it reversible. These standards are well defined in the art, and are standardized by the Universal Serial Bus Implementers Forum (USB-IF). This invention further teaches a reversible USB device. The phrase “USB device” is defined herein to include any device that is programmed or otherwise configured to perform a function and which includes a body attached to or integrally formed with a USB plug. The reversible USB devices of the present invention include a reversible USB plug such that the user can hold the body of the reversible device and engage it with a standard USB receptacle in either of two orientations. Finally, the invention further teaches a reversible USB appliance. The phrase “USB appliance” is defined herein to include any device that is programmed or otherwise configured to perform a function and which includes a body attached to or integrally formed with a USB receptacle. The reversible USB appliances of the present invention include a reversible USB receptacle (socket) such that the user can hold a standard USB device and engage it with the reversible USB receptacle of the appliance in either of two orientations. 
   Before turning to the specific implementations of the invention illustrated in the drawings, it will be helpful to present a conceptual description of the invention common to all of the embodiments described below. Thus, in general terms, the present invention provides a reversible connector (plug or receptacle) for coupling with a USB A-type standard connector (receptacle or plug), the standard connector having a hollow section, a fixed set of four electrical contacts disposed on one side of the hollow section and an electrically conducting shield disposed on three sides of the hollow section. The reversible connector of the present invention includes a first set of four electrical contact regions and a second set of four electrical contact regions. The first and second sets of electrical contact regions are configured such that, in a first coupling orientation of the reversible connector with the standard connector, the first set of electrical contact regions is mechanically connected with the set of electrical contacts of the standard connector and the second set is mechanically disconnected from the set of electrical contacts of the standard connector. The sets of contacts are further configured such that, in an alternative second coupling orientation of the reversible connector with the standard connector, the second set of electrical contact regions is mechanically connected with the set of electrical contacts of the standard connector and the first set is mechanically disconnected from the set of electrical contacts of the standard connector. 
   There are many possible mechanical solutions for implementing the underlying reversible connector concept of the present invention, all of which fall within the general scope of the present invention. By way of non-limiting examples, the invention will be exemplified below with reference to a small number of specific preferred examples. In some of these examples, the two sets of contacts are deployed on opposing sides of a single interface element so that one set of contacts is correctly oriented independent of the orientation of the interface element. The interface element may be a movable or flexible tongue or may be a rigid block. In other exemplary implementations described below, each set of contacts is deployed on a separate block and the blocks are selectively retractable to allow the appropriately oriented block to form the required connections. These options will be described in detail below. 
   For each implementation, correct connection of each set of contacts with the associated electronics of a USB device or appliance may be achieved in any or a large number of ways which will be clear to one ordinarily skilled in the art. By way of non-limiting examples, reference will be made below to three particular preferred connectivity options as follows: in a first option, an electronic switching arrangement is used to automatically switch between connections between the two sets of contacts; alternatively, a crossover arrangement of electrical contacts is used to connect both sets of contacts to a PCB in parallel; finally, a further option employs a modified PCB with eight separate input contacts, wherein the required connections may be achieved internally with or without switching. These options will be illustrated below. It should be noted, however, that the different options are interchangeable between the various embodiments described. 
   Ten embodiments of a reversible connector are described below. The first five embodiments, described with reference to  FIGS. 1   a  to  4   g , describe a reversible plug for connection to an A-type USB standard receptacle. The final five embodiments, described with reference to  FIGS. 5   a  to  8   g , describe a reversible receptacle for connection to an A-type USB standard plug. The overall resulting functionality of a reversible USB device, generic to the plug embodiments of  FIGS. 1   a - 4   g , is described with reference to  FIGS. 9   a - 9   h . Finally, an appliance containing a USB reversible receptacle, generic to the receptacle embodiments of  FIGS. 5   a - 8   g , is described with reference to  FIG. 10 . 
   It should be noted that, while the present description and the attached claims refer specifically to a reversible connector for connection to an A-type USB standard connector, this terminology should be interpreted by equivalents to encompass other existing or future connectors, having different standards but similar design considerations, for connecting two devices. 
   Reference is now made to  FIGS. 1   a - d .  FIG. 1   a  is an isometric view of a reversible plug  10  that is constructed and operable in accordance with a preferred embodiment of the present invention.  FIG. 1   b  is a plan view of reversible plug  10  of  FIG. 1   a .  FIG. 1   c  is a sectional view through the line C-C of  FIG. 1   b .  FIG. 1   d  is an exploded isometric view of reversible plug  10  of  FIG. 1   a . Reversible plug  10  has a sleeve  14 , a tongue arrangement  16  and a centering mechanism  18 . The phrase “tongue arrangement” as used herein in the description and claims refers to a generally flat arrangement (i.e., having two dimensions, “length” and “width”, significantly greater than a third “thickness” dimension) which is movable, at least under certain conditions, in a direction generally parallel to its thickness dimension, i.e., roughly perpendicular to its two larger dimensions. The dimensions referred to are the outer dimensions of the arrangement which may itself be an open structure with internal spaces as illustrated below in  FIGS. 2   a - 2   f ,  2   h - 2   m  and  6   a - 6   i , or a solid structure as illustrated here in  FIGS. 1   a - 1   d  and below in  FIGS. 5   a - 5   e . The movement of the tongue arrangement or part thereof may be a roughly parallel motion, or may be a flexing motion achieved through the flexibility of the tongue arrangement itself or a pivotal movement about an effective pivot axis. 
   Sleeve  14  is an electrically conducting shield configured to mate with the standard shielding configuration of a USB receptacle, and thus has four generally rectangular sides. Tongue arrangement  16  is initially centrally disposed in sleeve  14 . Tongue arrangement  16  includes a central insulating layer  20 . Central insulating layer  20  has an upper major side  22  and a lower major side  24 . It should be noted that, as reversible plug  10  is reversible, upper major side  22  may become the lower major side and lower major side  24  may become the upper major side. Nevertheless, the non-limiting terminology of “upper” and “lower” has been adopted for clarity of presentation in order to explain the present invention with reference to the drawings. Upper major side  22  has four grooves  26  therein. Similarly, lower major side  24  has four grooves (not shown) therein. Reversible plug  10  includes an upper set of electrical contact regions  28  recessed in grooves  26  of upper major side  22 . Similarly, reversible plug  10  includes a lower set of electrical contact regions  30  recessed in the grooves of lower major side  24 . Electrical contact regions  28  are electrically isolated from electrical contact regions  30  by central insulating layer  20 . Tongue arrangement  16  includes a bendable portion  32 . Bendable portion  32  enables tongue arrangement  16  to move up or down when coupled with a USB receptacle, as will be described below with reference to  FIGS. 1   e  and  1   f . Bendable portion  32  is typically a flexible element. However, it will be appreciated by those ordinarily skilled in the art that bendable portion  32  can also be a hinge or similar member. 
   Tongue arrangement  16  is preferably formed so as to center by itself elastically when not coupled with a USB receptacle. Nevertheless in order to ensure that tongue arrangement  16  is always centered within sleeve  14  prior to insertion into a USB receptacle, reversible plug  10  preferably also includes a centering mechanism  18  configured for maintaining tongue arrangement  16  centrally within sleeve  14 . Centering mechanism  18  will be described in more detail with reference to  FIGS. 1   e  and  1   f.    
   Reference is also made to  FIGS. 1   e  and  1   f .  FIG. 1   e  is an isometric view of reversible plug  10  of  FIG. 1   a  (having sleeve  14  removed for clarity) making contact with an A-type USB standard receptacle  34  (also having its outer housing removed for clarity).  FIG. 1   f  is a schematic semitransparent side view of reversible plug  10  and A-type USB standard receptacle  34  of  FIG. 1   e . A-type USB standard receptacle  34  has a shield  52  ( FIG. 1   f ) which surrounds a hollow section  48  on three sides. A set of four electrical contacts  50  is disposed on an insulating block  54  on one side of hollow section  48 . Electrical contacts  50  have projecting portions  51  which make electrical contact with either electrical contact regions  28  or electrical contact regions  30  of reversible plug  10 , as described below. Shield  52 , which is an electrically conducting shield, is disposed on the other three sides of hollow section  48 . Shield  52  has four sides so that hollow section  48  and insulating block  54  are surrounded by shield  52 . There is a gap between insulating block  54  and shield  52  so that sleeve  14  of reversible plug  10  is inserted between this gap when reversible plug  10  is coupled with A-type USB standard receptacle  34 . Insulating block  54  has a curved upper edge  56  at the entrance to A-type USB standard receptacle  34 . 
   Centering mechanism  18  includes two elongated side panels  36 . Each panel  36  has, at one end, a V-shaped notch  38  cut therein. The other end of each panel  36  is connected to a connecting member  40 . Panels  36  are connected to connecting member  40 , such that panels  36  are parallel to each other and the space between panels  36  accommodates tongue arrangement  16 . Centering mechanism  18  is typically formed as a unitary molded plastic element. Tongue arrangement  16  has a tip  42 . Tip  42  includes a protrusion  44  disposed on either side of tip  42  for engaging with V-shaped notches  38  of centering mechanism  18 . Centering mechanism  18  is retractable and is normally biased by an extension spring  46  to a forward position as shown in  FIG. 1   e  in which engagement of protrusions  44  with V-shaped notches  38  prevents centers and prevents up-down movement of tongue arrangement  16 . Therefore, centering mechanism  18  is a spring recoiled sliding locking mechanism. In this way, when reversible plug  10  is not connected to A-type USB standard receptacle  34 , tongue arrangement  16  is centered by means of centering mechanism  18 . 
   Initial contact of panels  36  of centering mechanism  18  with insulating block  54  of A-type USB standard receptacle  34  pushes panels  36  backward. This action releases protrusion  44  of tongue arrangement  16  from V-shaped notch  38  of centering mechanism  18  thereby allowing up and down movement of tongue arrangement  16 . 
   As reversible plug  10  is inserted into A-type USB standard receptacle  34 , tip  42  makes contact with curved upper edge  56  of insulating block  54 . Curved upper-edge  56  pushes tip  42  and therefore tongue arrangement  16  upward. Reversible plug  10  is inserted fully into hollow section  48 . At this point, only electrical contact regions  30  of lower major side  24  of tongue arrangement  16  make mechanical contact with electrical contacts  50  of A-type USB standard receptacle  34 . The term “only electrical contact regions  30 ” is defined herein to exclude electrical contact regions  28 . As electrical contact regions  28  of upper major side  22  are recessed in central insulating layer  20 , electrical contact regions  28  are electrically isolated from sleeve  14 . This is important to prevent shorting of electrical contact regions  28  with sleeve  14 . The above paragraph describes one coupling orientation of reversible plug  10  with A-type USB standard receptacle  34 . 
   A second coupling orientation is described below. In order to describe this coupling orientation, it is more convenient to consider a rotation of A-type USB standard receptacle  34  by 180 degrees so that insulating block  54  is above hollow section  48  rather than rotating reversible plug  10 . As reversible plug  10  is inserted into A-type USB standard receptacle  34 , tongue arrangement  16  is moved down. When reversible plug  10  is fully inserted, only electrical contact regions  28  of upper major side  22  of tongue arrangement  16  make mechanical contact with electrical contacts  50  of A-type USB standard receptacle  34 . The term “only electrical contact regions  28 ” is defined herein to exclude electrical contact regions  30 . Similarly, in this second coupling orientation, electrical contact regions  30  of lower major side  24  are electrically isolated from sleeve  14 . This implementation shows eight output connectors which may be connected directly to a suitably adapted printed circuit board, as will be clear to one ordinarily skilled in the art. As mentioned earlier, this connectivity solution is interchangeable with the alternative solutions of electronic switching and cross-over connection which will be described below. 
   Reference is now made to  FIGS. 2   a - c .  FIG. 2   a  is an isometric view of a reversible plug  58  that is constructed and operable in accordance with a first alternate embodiment of the present invention.  FIG. 2   b  is a front view of reversible plug  58  of  FIG. 2   a .  FIG. 2   c  is a sectional view through the line C-C of  FIG. 2   b . Reversible plug  58  is substantially the same as reversible plug  10  except for the differences described below and shown in  FIGS. 2   a  to  2   f . Reversible plug  58  has a tongue arrangement  66  formed from a first set of four electrical contact regions  60  and a second set of four electrical contact regions  62 . Tongue arrangement  66  is particularly distinguished from that of  FIGS. 1   a - 1   f  in that the metallic strips which provide electrical contact regions  60  and  62  themselves make up a primary structural element of the tongue arrangement. The term “primary structural element” is used herein to refer to an element or set of elements without which the structure described would not be self-supporting. The resulting structure is effectively a leaf spring electrical contact arrangement  64 . In other words, the primary structure of the tongue arrangement is resiliently flexible along most or all of its length such that the required up-down flexing of the tongue occurs by flexing of the entire structure without requiring a localized flexible region like the previous embodiment. Tongue arrangement  66  is initially centrally disposed in an electrically conducting sleeve  72  and preferably returns elastically to that central position. Electrical contact regions  60  and electrical contact regions  62  are typically from four metal strips which are bent to form leaf spring electrical contact arrangement  64 . However, it will be appreciated by those ordinarily skilled in the art that leaf spring electrical contact arrangement  64  can be formed from eight or more metal strips which are then joined together to form leaf spring electrical contact arrangement  64 . There is no central insulating layer in this embodiment. The individual leaf spring electrical contacts are connected at their tips via an insulated cap  68 . 
   Reference is now made to  FIG. 2   d , which is a sectional view of reversible plug  58  of  FIG. 2   a  making contact with A-type USB standard receptacle  34 . Insulated cap  68  has a pointed end so that tongue arrangement  66  is pushed up or down (depending on the coupling orientation of reversible plug  58  and A-type USB standard receptacle  34 ) when inserted into A-type USB standard receptacle  34  via curved upper edge  56  of insulating block  54  of A-type USB standard receptacle  34 . In the example of  FIG. 2   d , tongue arrangement  66  will be pushed up when inserted into hollow section  48  of A-type USB standard receptacle  34 . 
   Reference is now made to  FIG. 2   e , which is a sectional view of reversible plug  58  and A-type USB standard receptacle  34 , fully coupled. Insulated cap  68  is configured for preventing electrical contact between leaf spring electrical contact arrangement  64  and sleeve  72  in both coupling orientations of reversible plug  58  with A-type USB standard receptacle  34 . Additionally, insulated cap  68  and leaf spring electrical contact arrangement  64  are configured such that leaf spring electrical contact arrangement  64  makes electrical contact with projecting portions  51  of electrical contacts  50  of A-type USB standard receptacle  34  in both coupling orientations of reversible plug  58 . Therefore, each contact of leaf spring electrical contact arrangement  64  forms a diamond shape at the tip of tongue arrangement  66 . The half of the diamond shape closest to the tip of tongue arrangement  66  is covered by insulated cap  68 . The other half of the diamond shape is not insulated so that this portion of the diamond makes electrical contact with projecting portions  51  of electrical contacts  50 . The diamond shape is configured so that it makes maximum contact with projecting portions  51 . 
   Reference is now made to  FIG. 2   f , which is an isometric view of reversible plug  58  and A-type USB standard receptacle  34  of  FIG. 2   e  fully coupled (having their outer housings removed for clarity). As each of electrical contact regions  60  is electrically connected with a corresponding electrical contact region  62 , electrical signals from leaf spring electrical contact arrangement  64  need to be routed according to the coupling orientation of reversible plug  58  with A-type USB standard receptacle  34 . Therefore, reversible plug  58  includes an electronic switching arrangement  70  configured for routing electrical signals from leaf spring electrical contact arrangement  64  according to the coupling orientation of tongue arrangement  66  with A-type USB standard receptacle  34 . It will be appreciated by those ordinarily skilled in the art how to design and produce a suitable device for performing the function of electronic switching arrangement  70 . A preferred example of electronic switching arrangement  70  is described below. 
   Reference is now made to  FIG. 2   g , which is a schematic view of electronic switching arrangement  70  for use with plug  58  of  FIG. 2   a . Reversible plug  58  has two power pins and two data pins. Electronic switching arrangement  70  includes a power detection circuit  61 , a power inversion arrangement  63  and a data inversion arrangement  65 . One of the power pin outputs of reversible plug  58  is inputted into power detection circuit  61 . Power detection circuits  61  can be electrically connected to either output pin of reversible plug  58 . The output of power detection circuit  61  is fed into data inversion arrangement  65 . Additionally, the output of the data pins of reversible plug  58  is fed into data inversion arrangement  65 . Data inversion arrangement  65  is configured for routing the output of the data pins in accordance with the output of power detection circuit  61 , thereby inverting the output if necessary. Data inversion arrangement  65  is typically an analog switch, compliant with USB 2.0, for example, but not limited to ADG 3257. Power inversion arrangement  63  inverts the power output if necessary. Power inversion arrangement  63  is typically a Darlington Bridge diode circuit. 
   Reference is now made to  FIGS. 2   h  to  2   k .  FIG. 2   h  is a sectional view of a reversible plug  240 , that is constructed and operable in accordance with a second alternate embodiment of the present invention, making contact with an A-type USB standard receptacle  242 .  FIG. 2   i  is a sectional view of reversible plug  240  and A-type USB standard receptacle  242  of  FIG. 2   h  fully coupled.  FIG. 2   j  is an isometric view of reversible plug  240  and A-type USB standard receptacle  242  of  FIG. 2   h  fully coupled (having their outer housing removed for clarity).  FIG. 2   k  is a top view of tongue arrangement  252  of reversible plug  240  of  FIG. 2   h .  FIG. 2   m  is an isometric view of tongue arrangement  252  of  FIG. 2   k . Reversible plug  240  is substantially the same as reversible plug  58  of  FIGS. 2   a  to  2   g  except for the differences described below and shown in  FIGS. 2   h  to  2   m . Reversible plug  240  includes a tongue arrangement  252  having an insulating layer  244  disposed between a set of electrical contact regions  246  and a set of electrical contact regions  248 . Set of electrical contact regions  246  and set of electrical contact regions  248  are formed as a leaf spring electrical contact arrangement  250 . Set of electrical contact regions  246  and set of electrical contact regions  248  are not electrically connected at a tip  254  of tongue arrangement  252 . As with reversible plug  58 , the primary structural element of tongue arrangement  252  of reversible plug  240  is the set of metallic strips which also function as a leaf spring electrical contact arrangement  250 . Insulating layer  244  is primarily for electrically isolating set of electrical contact regions  246  and set of electrical contact regions  248  over the flexible portion of tongue arrangement  252 . Reversible plug  240  also includes a printed circuit board interface connector arrangement  256  having four terminals  258  disposed thereon. Each terminal  258  is configured for connection to a printed circuit board  260 . Printed circuit board interface connector arrangement  256  has a crossover arrangement  262  for electrically connecting electrically corresponding contact regions of set of electrical contact regions  246  and set of electrical contact regions  248  to terminals  258 . The term “electrically corresponding contact region” is defined herein as contact regions of reversible plug  240  which make electrical contact with the same electrical contact of A-type USB standard receptacle  242 . Therefore, in whichever coupling orientation reversible plug  240  is inserted into A-type USB standard receptacle  242 , the same terminals of A-type USB standard receptacle  242  are in electrical contact with the same terminals  258  of printed circuit board interface connector arrangement  256 . Therefore, electronic switching arrangement  70  is not needed in this embodiment. It should be noted that the arrangement of terminals  258  differs from the standard USB pin arrangement for connection to a printed circuit board. The arrangement shown in  FIGS. 2   h  to  2   m  has been chosen in order to simplify the figures. However, it will be appreciated by those ordinarily skilled in the art that terminals  258  can be arranged in accordance with a standard USB pin arrangement for connection to a printed circuit board. 
   Reference is now made to  FIGS. 3   a - d .  FIG. 3   a  is an isometric view of a reversible plug  74  that is constructed and operable in accordance with a third alternate embodiment of the present invention.  FIG. 3   b  is a plan view of reversible plug  74  of  FIG. 3   a .  FIG. 3   c  is a sectional view through line C-C of  FIG. 3   b .  FIG. 3   d  is a sectional view through line D-D of  FIG. 3   b . Reversible plug  74  includes an interface element  73  similar to the tongue arrangement of the first three embodiments. Unlike the first three embodiments, reversible plug  74  does not in this case have a shield or sleeve which surrounds interface element  73 . As a result of the absence of an outer sleeve, interface element  73  may be rigidly mounted without freedom of up-down movement relative to a device to which it is attached. Instead, the interface element centers itself within the socket together with the entire device during insertion. Interface element  73  as illustrated here includes a central insulting layer  75  having an upper major surface  76  and a lower major surface  78 . Central insulting layer  75  is substantially rigid. The term “substantially rigid” as used herein implies that the major structural element of the central insulating layer is relatively rigid. It should be noted however that the element may additionally include minor surface features and projections disposed on central insulting layer  75 , some of which may be flexible, as will be described below. Upper major surface  76  includes four grooves in which a set of four electrical contacts  80  is recessed. Lower major surface  78  includes four grooves in which a set of four electrical contacts  82  is recessed. 
   Reversible plug  74  includes a projection  84  disposed on either side of central insulting layer  75 . Reversible plug  74  also includes two projections  86  disposed on upper major surface  76  and lower major surface  78 . Projections  84 ,  86  are configured for centering interface element  73  within hollow section  48  of A-type USB standard receptacle  34  as well as reducing lateral movement of interface element  73  within hollow section  48  of A-type USB standard receptacle  34 . Projections  84 ,  86  are typically flexible projections which are formed integrally with central insulting layer  75 . Projections  86  additionally prevent electrical contacts  80  and electrical contacts  82  from making electrical contact with shield  52  of A-type USB standard receptacle  34 , as will be explained below with reference to  FIG. 3   f.    
   Reference is now  FIGS. 3   e  and  3   f .  FIG. 3   e  is a plan view of reversible plug  74  of  FIG. 3   a  inserted into A-type USB standard receptacle  34 .  FIG. 3   f  is a sectional view through the line F-F of  FIG. 3   e . In the example of  FIGS. 3   e  and  3   f , reversible plug  74  is inserted into A-type USB standard receptacle  34  in a first coupling orientation. In this coupling orientation, electrical contacts  80  of upper major surface  76  are in electrical contact with electrical contacts  50  of A-type USB standard receptacle  34 . Projections  86  prevent electrical contacts  82  of lower major surface  78  coming into electrical contact with shield  52  of A-type USB standard receptacle  34 . 
   Similarly, if either reversible plug  74  or A-type USB standard receptacle  34  are turned over, electrical contacts  82  of lower major surface  78  make contact with electrical contacts  50  of A-type USB standard receptacle  34  when reversible plug  74  is coupled with A-type USB standard receptacle  34  in a second coupling orientation. Similarly, in this second coupling orientation, projections  86  prevent electrical contacts  80  from making electrical contact with shield  52 . 
   Reference is now made to  FIGS. 4   a - e .  FIG. 4   a  is an isometric view of a reversible plug  90  that is constructed and operable in accordance with a fourth alternate embodiment of the present invention.  FIG. 4   b  is a plan view of reversible plug  90  of  FIG. 4   a .  FIG. 4   c  is a sectional view through line C-C of  FIG. 4   b .  FIG. 4   d  is a sectional view through line D-D of  FIG. 4   c .  FIG. 4   e  is an exploded view of reversible plug  90  of  FIG. 4   a . Reversible plug  90  includes a sleeve  92  and a pair of blocks  94  slidably mounted adjacent to each other in sleeve  92 . Sleeve  92  is an electrically conducting shield. Blocks  94  are configured for independently sliding between an operative position and a retracted position as will be explained in more detail with reference to  FIGS. 4   e  and  4   f . The term “independently sliding” is defined herein as each block slides between its operative position and its retracted position independently of the position of the other block. Sleeve  92  has two open ends, one at the rear of sleeve  92  and one at the end of sleeve  92  which couples with A-type USB standard receptacle  34 . The open end of sleeve  92  which couples with A-type USB standard receptacle  34  is defined as coupling open end  96 . The operative position is where blocks  94  are level with coupling open end  96  of sleeve  92 . The retracted position is where blocks  94  are pushed into sleeve  92  as far as they will move due to the constraints of reversible plug  90 . Blocks  94  include an upper block  98  and a lower block  100 . A set of four electrical contacts  102  is recessed into four grooves in the lower surface  104  of upper block  98 . Similarly, a set of four electrical contacts  106  is recessed into four grooves in the upper surface  108  of lower block  100 . Therefore, electrical contacts  102  face electrical contacts  106  when both upper block  98  and lower block  100  are in the operative position. Each block  94  includes four channels  132  therein. Electrical contacts  102  and electrical contacts  106  continue from lower surface  104  and upper surface  108 , respectively, through channels  132  to the other side of upper block  98  and lower block  100 , respectively. Therefore, there are external contact regions  138  of electrical contacts  102  and electrical contacts  106  on the upper surface  134  of upper block  98  and the lower surface  136  of lower block  100 , respectively. The function of external contact regions  138  is described in more detail below. Blocks  94  are typically formed from one or more molded plastic sections. 
   Reversible plug  90  also includes a rear housing  116  disposed around the rear portion of sleeve  92 . Rear housing  116  has a top rectangular plate  118 , a lower rectangular plate  120  and a central rectangular plate  122 . One end of top rectangular plate  118  is connected to central rectangular plate  122 . Similarly one end of lower rectangular plate  120  is connected to central rectangular plate  122 . Rear housing  116  is typically formed as a unitary molded plastic or element. The top surface of top rectangular plate  118  has a plurality of grooves  124  therein for recessing a plurality of electrical terminals  126  therein. Similarly, the bottom of surface of lower rectangular plate  120  has a plurality of grooves  128  therein for recessing a plurality of electrical terminals  130  therein. Each groove  124  terminates, at the end closest to coupling open end  96  of sleeve  92 , with an opening  142  in the surface of top rectangular plate  118 . Electrical terminals  126  continue through openings  142  in order to make electrical contact with external contact regions  138  of electrical contacts  102  when upper block  98  is in the operative position (best seen in  FIG. 4   c ). Similarly, each groove  128  terminates, at the end closest to coupling open end  96  of sleeve  92 , with an opening  144  in the surface of lower rectangular plate  120 . Electrical terminals  130  continue through openings  144  in order to make electrical contact with external contact regions  138  of electrical contacts  106  when lower block  100  is in the operative position. The middle region of the upper surface and lower surface of sleeve  92  has a rectangular opening  140  therein so that electrical terminals  126  and electrical terminals  130  make electrical contact with electrical contacts  102  and electrical contacts  106 , when upper block  98  and lower block  100  are in the operative position, respectively. 
   Blocks  94  include a restoring arrangement  110  configured for restoring blocks  94  to the operative position. Restoring arrangement  110  typically includes two helical springs, one spring for each block  94 . Each spring is disposed between its respective block  94  and central rectangular plate  122  of rear housing  116 . Each block  94  has a width and a thickness. The thickness is defined as the minimum outside dimension of the surface exposed at coupling open end  96  of sleeve  92 . It is desirable to use helical springs having an outer diameter greater than the thickness of each block  94 . This is because narrower springs are not robust enough and are not readily available. Therefore, blocks  94  have cut out portions  112  and overlapping portions  114  at their rear. Cut out portions  112  of one block  94  are configured to accommodate overlapping portions  114  of the other block  94 , and vice-versa (best seen in  FIGS. 4   c - e ). In this way, helical springs having an outer diameter greater than the thickness of each block  94  are used without making the overall reversible plug  90  too bulky. 
   Reference is now made to  FIGS. 4   f  and  4   g .  FIG. 4   f  is a plan view of reversible plug  90  of  FIG. 4   a  inserted into A-type USB standard receptacle  34 ,  FIG. 4   g  is a sectional view through line G-G of  FIG. 4   f . Depending upon the coupling orientation of reversible plug  90  with A-type USB standard receptacle  34  one of blocks  94  is pushed back to the retracted position by insulating block  54  of A-type USB standard receptacle  34 . The other block remains in the operative position so that its electrical contacts make contact with electrical contacts  50  of A-type USB standard receptacle  34 . In the example of  FIGS. 4   f  and  4   g , a first coupling orientation of reversible plug  90  with A-type USB standard receptacle  34 , upper block  98  is moved by insulating block  54  of A-type USB standard receptacle  34  to the retracted position. Lower block  100  remains in the operative position with electrical contacts  106  in electrical contact with electrical contacts  50  of A-type USB standard receptacle  34 . 
   Similarly, if either reversible plug  90  or A-type USB standard receptacle  34  is turned over, reversible plug  90  and A-type USB standard receptacle  34  couple in a second coupling orientation. In this second coupling orientation, lower block  100  is moved by insulating block  54  of A-type USB standard receptacle  34  to the retracted position. Upper block  98  remains in the operative position with electrical contacts  102  in electrical contact with electrical contacts  50  of A-type USB standard receptacle  34 . 
   When either of blocks  98 ,  100  are pushed back from the operative position to the retracted position electrical contacts  102  and electrical contacts  106  are electrically isolated from electrical terminals  126  and electrical terminals  130 , respectively. 
   Referring now to  FIGS. 9   a - 9   h , schematic block diagrams depicting a reversible device that is constructed and operable in accordance with a preferred embodiment of the present invention. It should be noted that the term USB device is defined herein as an apparatus containing a USB plug, where as a USB appliance is defined herein as an apparatus containing a USB receptacle. Reversible USB device  306  includes a functional unit  308 . Functional unit  308  is configured to perform at least one function, a non-limiting example of which is the storing of data packages on reversible USB device  306 . Reversible USB device  306  further includes a reversible USB plug  304  which is connected to functional unit  308  and is used for interconnecting functional unit  308  with appliance  302 . Reversible plug  304  conforms with any of the above mentioned embodiments or one of their possible derivatives. Reversible device  306  also consists of a body  309 , serving as a physical encasement and housing for functional unit  308 . Body  309  is constructed so it may be gripped by the user, being the physical element that is held by the user when attempting to engage reversible USB device  306  with appliance  302 . Reversible plug  304  protrudes directly from body  309  in a rigid manner, or at least in a non-rotatable manner, and is situated asymmetrically in relation to the sides of body  309 , the asymmetric positioning being for aesthetic or functional reasons. Appliance  302  contains a standard USB receptacle  300 .  FIG. 9   a  shows reversible USB device  306  positioned in a first coupling orientation in relation to appliance  302  and aligned for insertion. Yet, appliance  302  has a physical structure which prevents the insertion of reversible USB device  306  into standard USB receptacle  300  in a first coupling orientation. The coupling orientation of reversible device  306  is changed by the turning over of device  306 , as can be seen in  FIG. 9   b . In the second coupling orientation ( FIG. 9   c ) the physical structure of appliance  302  does not prevent the insertion of reversible USB device  306  into standard USB receptacle  300 . Reversible USB plug  304 , which may be inserted into a standard receptacle in both first and second coupling orientation, is coupled with standard receptacle  300  ( FIG. 9   d ) thus connecting reversible device  306  and appliance  302  in the prescribed manner.  FIGS. 9   e - 9   h  show another example of the coupling of reversible USB device  306  and an appliance containing a standard USB receptacle. Appliance  314  contains a standard USB receptacle  310  which is to be coupled with reversible USB plug  304  of reversible device  306 . Appliance  314  further contains another standard USB receptacle  312 . As can be seen in  FIG. 9   e , reversible USB device  306  is aligned with standard USB receptacle  310  in a first coupling orientation. In this orientation, the body of reversible USB device  306  obstructs the hollow opening of standard USB receptacle  312  due to the proximity of neighboring standard receptacles  310  and  312 . Thus, another device employing a USB plug (not shown) may not be inserted into and coupled with standard receptacle  312 . It should be noted that receptacle  312  is exemplary and may be any port, display or general feature that is obstructed by the physical structure of reversible USB device  306 . The coupling orientation of reversible USB device  306  is changed by extracting device  306  from the standard receptacle  300  ( FIG. 9   f ) and turning it over ( FIG. 9   g ) in the same manner as has been described in  FIG. 9   b .  FIG. 9   h  shows reversible USB device  306  coupled with standard USB receptacle  310  in a second coupling orientation, receptacle  312  being unobstructed, thus allowing the coupling of another USB device with it (not shown). 
   The next four embodiments relate to embodiments of a reversible receptacle for coupling with an A-type USB standard plug. 
   Reference is now made to  FIGS. 5   a  and  5   b ,  FIG. 5   a  is an isometric view of a reversible receptacle (socket)  146  that is constructed and operable in accordance with a preferred embodiment of the present invention.  FIG. 5   b  is an exploded isometric view of reversible receptacle  146  of  FIG. 5   a . Reversible receptacle  146  is substantially the same as reversible plug  10  of  FIGS. 1   a - f  except for the following differences described below and in  FIGS. 5   a  to  5   e . Reversible receptacle  146  has a sleeve  148 . Sleeve  148  is an electrically conducting shield, similar to shield  52  of A-type USB standard receptacle  34 . Reversible receptacle  146  has a tongue arrangement  150  having a central insulating layer  152  with a set of electrical contacts  154  disposed in grooves  156  on an upper side  158  of central insulating layer  152  and another set of electrical contacts  166  disposed in grooves on a lower side  162  of central insulating layer  152 . Tongue arrangement  150  is hinged so tongue arrangement  150  is able to move up and down. Reversible receptacle  146  has a centering mechanism  164  which operates substantially the same as centering mechanism  18  of reversible plug  10 . 
   Reference is now made to  FIGS. 5   c  and  5   d .  FIG. 5   c  is a plan view of reversible receptacle  146  of  FIG. 5   a  making contact with an A-type USB standard plug  168 .  FIG. 5   d  is a sectional view through line D-D of  FIG. 5   c . A-type USB standard plug  168  has a hollow  170  surrounded on three sides by an electrically conducting shield  172 . A block  174  having a set of four electrical contacts  176  thereon is disposed on a fourth side of hollow  170 . Block  174  has a beveled edge  178  toward the center of shield  172 . As reversible receptacle  146  is inserted into A-type USB standard plug  168 , centering mechanism  164  is released and beveled edge  178  of block  174  of A-type USB standard plug  168  pushes tongue arrangement  150  upward. 
   Reference is now made to  FIG. 5   e , which is a sectional view of reversible receptacle  146  and A-type USB standard plug  168  of  FIG. 5   c  fully coupled. By way of introduction, electrical contacts  50  of A-type USB standard receptacle  34  have projecting portions  51  which make electrical contact with the flat contacts of the plug inserted into hollow section  48  of A-type USB standard receptacle  34 . If the contacts of A-type USB standard receptacle  34  did not have projections, contact would not be made between electrical contacts  50  of A-type USB standard receptacle  34  and the flat contacts of a USB plug. Therefore, electrical contacts  154  and electrical contacts  166  of reversible receptacle  146  need to have projecting portions so that electrical contacts  154  and electrical contacts  166  make contact with the flat contacts of an A-type USB standard plug. However, if both electrical contacts  154  and electrical contacts  166  had projecting portions, the projecting portions would interfere with coupling of reversible receptacle  146  and A-type USB standard plug  168  since the metal sleeve surface of the standard plug facing its contacts does not have recesses to accommodate such projections. Additionally, inserting A-type USB standard plug  168  in a first orientation would result in the projecting portions of electrical contacts  154  making contact with shield  172  of A-type USB standard plug  168  and thereby short-circuiting the electrical contacts of reversible receptacle  146 , a similar situation occurs when inserting standard plug  168  in a second orientation. Therefore, electrical contacts  154  and electrical contacts  166  are generally recessed below the surface of central insulating layer  152  and are configured to be selectively deflected away from central insulating layer  152  when required, as will be described below. 
   Reversible receptacle  146  includes a contact raising arrangement  180 . In the example of  FIG. 5   e , reversible receptacle  146  is in a first coupling orientation with A-type USB standard plug  168 . Contact raising arrangement  180  is configured for deflecting electrical contacts  166  away from tongue arrangement  150 , so that electrical contacts  166  make mechanical contact with the electrical contacts  176  of A-type USB standard plug  168 . The term “deflecting away from tongue arrangement” is defined herein as moving the electrical contacts away from central insulating layer  152 . The phrase “contact raising” is used herein to refer to a localized deflection of one or more metallic strip providing a contact region towards the corresponding surface with which it is to make electrical contact. Electrical contacts  154  remain recessed below central insulating layer  152  and therefore electrical contacts  154  are electrically isolated from shield  172  of A-type USB standard plug  168 . 
   Similarly, in a second coupling orientation (not shown) of reversible receptacle  146  and A-type USB standard plug  168 , electrical contacts  154  are deflected away from tongue arrangement  150 , so that electrical contacts  154  makes mechanical contact with electrical contacts  176  of A-type USB standard plug  168 . Electrical contacts  166  remain recessed below central insulating layer  152  and therefore electrical contacts  166  are electrically isolated from shield  172  of A-type USB standard plug  168 . 
   Contact raising arrangement  180  is formed as part of electrical contacts  166  and electrical contacts  154  as follows. Each electrical contact  154 ,  166  has a doubled over portion towards its middle to form a loop  182 . Each loop  182  is covered by an insulating cap  183 . Loop  182  is pushed by block  174  just before reversible receptacle  146  is fully coupled with A-type USB standard plug  168 . Pushing loop  182  deflects the associated contact way from tongue arrangement  150 . For example, in the first coupling orientation, loops  182  of electrical contacts  166  are pushed by block  174  thereby deflecting electrical contacts  166  away from tongue arrangement  150 . However, loops  182  of electrical contacts  154  are not moved and therefore electrical contacts  154  remain recessed in tongue arrangement  150 . 
   Reference is now made to  FIGS. 6   a - 6   c .  FIG. 6   a  is an isometric view of a reversible receptacle  184  (without its accompanying circuit board) that is constructed and operable in accordance with a first alternate embodiment of the present invention.  FIG. 6   b  is a plan view of reversible receptacle  184  of  FIG. 6   a  (with its accompanying circuit board  186 ).  FIG. 6   c  is an exploded isometric view of reversible receptacle  184  of  FIG. 6   c . Reversible receptacle  184  is substantially the same as reversible plug  58  of  FIGS. 2   a - 2   f  except for the differences described below and shown in  FIGS. 6   a  to  6   c . Reversible receptacle  184  has a sleeve  185  with is substantially the same as sleeve  148  of reversible receptacle  146  of  FIG. 5   a . Reversible receptacle  184  has a tongue arrangement  188  centrally disposed in sleeve  185 . Tongue arrangement  188  has an upper set of contact regions  190  and a lower set of contact regions  192 . Upper set of contact regions  190  and lower set of contact regions  192  form a leaf spring electrical contact arrangement  194 . Tongue arrangement  188  has an insulated cap  196  disposed at the tip of tongue arrangement  188 . Insulated cap  196  is described in more detail with reference to  FIGS. 6   d  and  6   e . Each contact of upper set of contact regions  190  and lower set of contact regions  192  is doubled over towards the middle of each contact to form a plurality of loops  198  projecting from tongue arrangement  188 . Loops  198  of upper set of contact regions  190  are covered with an insulating cover  200 . Similarly, loop  198  of lower set of contact regions  192  are covered with an insulating cover  202 . Insulating covers  200  and  202  provide protection against the loops  198  becoming shorted against the outer shielding of the plug. Loops  198 , insulating cover  200  and insulating cover  202  form a tongue actuator  208  which is described in more detail with reference to  FIG. 6   e.    
   A set of four electrical terminals  204  is disposed on accompanying circuit board  186 . Electrical terminals  204  are connected to the rear of leaf spring electrical contact arrangement  194  and an electronic switching arrangement  206 . Electronic switching arrangement  206  performs the same function as electronic switching arrangement  70  of reversible plug  58  of  FIG. 2   f.    
   Reference is now made to  FIG. 6   d , which is a sectional of reversible receptacle  184  of  FIG. 6   b  through line D-D making contact with A-type USB standard plug  168 . As A-type USB standard plug  168  is inserted into reversible receptacle  184 , tongue arrangement  188  is pushed up by beveled edge  178  of block  174  of A-type USB standard plug  168 . Tongue arrangement  188  is pushed up so much that tongue arrangement  188  touches shield  172  of A-type USB standard plug  168 . Therefore, insulated cap  196  is configured for preventing electrical contact between leaf spring electrical contact arrangement  194  and shield  172  of A-type USB standard plug  168  as tongue arrangement  188  couples with hollow  170  of A-type USB standard plug  168 . In other words, insulated cap  196  and leaf spring electrical contact arrangement  194  are configured so that when a central plane of tongue arrangement  188  makes an acute angle with shield  172 , the first part of tongue arrangement  188  to make contact with shield  172  is insulated cap  196 . Therefore, leaf spring electrical contact arrangement  194  is prevented from making contact with shield  172 . 
   Reference is now made to  FIG. 6   e , which is a sectional view of reversible receptacle  184  and A-type USB standard plug  168  of  FIG. 6   d , fully coupled. As A-type USB standard plug  168  is pushed further into hollow  170  of reversible receptacle  184 , block  174  of A-type USB standard plug  168  pushes on tongue actuator  208 . Tongue actuator  208 , in turn, points tongue arrangement  188  back down towards the electrical contacts  176  of A-type USB standard plug  168  so that the central plane of tongue arrangement  188  is approximately horizontal. Insulated cap  196  and leaf spring electrical contact arrangement  194  are configured such that, as tongue arrangement  188  is pointed back down with the central plane of tongue arrangement  188  approximately horizontal, the first part of tongue arrangement  188  to make contact with electrical contacts  176  is leaf spring electrical contact arrangement  194 . Therefore, insulated cap  196  does not prevent leaf spring electrical contact arrangement  194  from making contact with electrical contacts  176 . Therefore, insulated cap  196  and leaf spring electrical contact arrangement  194  need to be configured to: (a) prevent contact between leaf spring electrical contact arrangement  194  when tongue arrangement  188  is pointing up toward shield  172 ; and (b) allow contact between leaf spring electrical contact arrangement  194  and electrical contacts  176  when tongue arrangement  188  is pointed back down. Leaf spring electrical contact arrangement  194  and insulated cap  196  are symmetrical about the central plane of tongue arrangement  188  so that in a second coupling orientation leaf spring electrical contact arrangement  194  makes contact with electrical contacts  176 , but leaf spring electrical contact arrangement  194  does not make contact with shield  172 . 
   Reference is now made to  FIGS. 6   f  to  6   i .  FIG. 6   f  is a sectional view of a reversible receptacle  264  that is constructed and operable in accordance with a second alternate embodiment of the present invention.  FIG. 6   g  is an exploded isometric view of reversible receptacle  264  of  FIG. 6   f .  FIG. 6   h  is a rear isometric view of a tongue arrangement  266  of reversible receptacle  264  of  FIG. 6   f .  FIG. 6   i  is a front isometric view of tongue arrangement  266  of  FIG. 6   h . Reversible receptacle  264  is substantially the same as reversible receptacle  184  of  FIGS. 6   a  to  6   e  except for the differences described below and shown in  FIGS. 6   f  to  6   i . Tongue arrangement  266  has an insulating layer  270  disposed between a set of electrical contact regions  272  and a set of electrical contact regions  274 . Set of electrical contact regions  272  and set of electrical contact regions  274  are formed as a leaf spring electrical contact arrangement  276 . Set of electrical contact regions  272  and set of electrical contact regions  274  are not electrically connected at a tip  278  of tongue arrangement  266 . As with reversible receptacle  184 , the primary mechanical element of tongue arrangement  266  of reversible receptacle  184  is the set of metallic strips which also serves as a leaf spring electrical contact arrangement  276 . Insulating layer  270  is primarily for electrically isolating set of electrical contact regions  272  and set of electrical contact regions  274  over the flexible portion of tongue arrangement  266 . Reversible receptacle  264  also includes a printed circuit board interface connector arrangement  280  having four terminals  282  disposed thereon. Each terminal  282  is configured for connection to a printed circuit board  284 . Printed circuit board interface connector arrangement  280  has a crossover arrangement  286  for electrically connecting electrically corresponding contact regions of set of electrical contact regions  272  and set of electrical contact regions  274  to terminals  282 . Therefore, in whichever coupling orientation reversible receptacle  264  is inserted into an A-type USB standard plug, the same terminals of the A-type USB standard plug are in electrical contact with the same terminals  282  of printed circuit board interface connector arrangement  280 . 
   Reference is now made to  FIGS. 7   a - c .  FIG. 7   a  is an isometric view of a reversible receptacle  210  that is constructed and operable in accordance with a third alternate embodiment of the present invention.  FIG. 7   b  is a plan view of reversible receptacle  210  of  FIG. 7   a .  FIG. 7   c  is a sectional view through line C-C of  FIG. 7   b . Reversible receptacle  210  is substantially the same as reversible plug  74  except that reversible receptacle  210  has selectively raisable contacts  212  on both sides of reversible receptacle  210  using a mechanism similar to the contact raising mechanism described above. Additionally, reversible receptacle  210  does not have flexible surface projections included with reversible plug  74 . 
   Reference is now made to  FIG. 7   d , which is a sectional view of reversible receptacle  210  of  FIG. 7   c  coupled with A-type USB standard plug  168 .  FIG. 7   d  shows a first coupling orientation of reversible receptacle  210  with A-type USB standard plug  168 . The lower raisable contacts  212  are deflected away from the interface element of reversible receptacle  210  in order to make contact with electrical contacts  176  of A-type USB standard plug  168 . The upper raisable contacts  212  remain recessed in the interface element of reversible receptacle  210  to prevent shorting with shield  172  of A-type USB standard plug  168 . 
   Reference is now made to  FIG. 8   a - 8   c .  FIG. 8   a  is an isometric view of a reversible receptacle  214  that is constructed and operable in accordance with a fourth alternate embodiment of the present invention.  FIG. 8   b  is an exploded isometric view of reversible receptacle  214  of  FIG. 8   a .  FIG. 8   c  is an exploded isometric view of a lower block  216  of reversible receptacle  214  of  FIG. 8   b . Reversible receptacle  214  is substantially the same as reversible plug  90  of  FIGS. 4   a - 4   g  except for the following differences described below and shown in  FIGS. 8   a  to  8   g . Reversible receptacle  214  has a sleeve  220  which is the same as sleeve  148  of  FIG. 5   a . As sleeve  220  is shorter than sleeve  92  of reversible plug  90 , rectangular openings  140  disposed in reversible plug  90  are not needed in sleeve  220 . Additionally, as reversible receptacle  214  couples with the flat electrical contacts  176  of A-type USB standard plug  168 , the contacts of reversible receptacle  214  need to be raisable. Reversible receptacle  214  includes lower block  216  and an upper block  218 . Lower block  216  has a set of four recessed electrical contacts  222  with loops. Upper block  218  has a set of four recessed electrical contacts  224  with loops. The loops of electrical contacts  222  are mechanically connected via an insulating element  226  having two actuating levers  228  thereon. Actuating levers  228  are configured to be pushed by A-type USB standard plug  168  when reversible receptacle  214  and A-type USB standard plug  168  are coupled in order to raise electrical contacts  222 . Similarly, electrical contacts  224  are connected via an insulting element  230  having two actuating levers  232  thereon. Upper block  218  includes two grooves  234  disposed between the grooves of electrical contacts  224  to accommodate actuating levers  228  of electrical contacts  222  of lower block  216  during relative movement of lower block  216  and upper block  218 . Similarly, lower block  216  includes two grooves  236  disposed between the grooves of electrical contacts  222  to accommodate actuating levers  232  of electrical contacts  224  of upper block  218  during relative movement of lower block  216  and upper block  218 . 
   Reference is now made to  FIGS. 8   d - e .  FIG. 8   d  is a plan view of reversible receptacle  214  of  FIG. 8   a  making contact with A-type USB standard plug  168 .  FIG. 8   e  is a sectional view through line E-E of  FIG. 8   d.    
   Reference is now made to  FIGS. 5   f  and  8   g .  FIG. 8   f  is a sectional view of reversible receptacle  214  and A-type USB standard plug  168  of  FIG. 8   d , fully coupled.  FIG. 8   g  is an isometric view of reversible receptacle  214  of  FIG. 8   f  (having sleeve  220  removed for clarity) when fully coupled with A-type USB standard plug  168  of  FIG. 8   f , A-type USB standard plug  168  being removed for clarity.  FIGS. 8   f  and  8   g  show a first coupling orientation of reversible receptacle  214  and A-type USB standard plug  168 . Upper block  218  has been pushed back to the retracted position by block  174  of A-type USB standard plug  168 . Additionally, block  174  pushes actuating levers  228  which raises electrical contacts  222  away from lower block  216  so that electrical contacts  222  makes mechanical and electrical contact with electrical contacts  176  of A-type USB standard plug  168 . 
   Similarly, in a second coupling orientation electrical contacts  224  are raised away from upper block  218  so that electrical contacts  224  make contact with electrical contacts  176  of A-type USB standard plug  168 . 
   Referring now to  FIG. 10 , a schematic block diagram depicting an appliance incorporating a reversible USB receptacle with relation to a device containing a standard USB plug. Reversible USB appliance  324  includes functional unit  321 . Functional unit  321  is configured to perform at least one function, a non-limiting example of which is performing mathematical operations. Appliance  324  further contains a reversible USB receptacle  326  which is connected to functional unit  321  and is used for interconnecting functional unit  321  with USB device  320 . Reversible receptacle  326  conforms with any of the above mentioned embodiments or one of their possible derivatives. Reversible USB appliance  324  also consists of a body  325 , serving as a physical encasement and housing for functional unit  321 . Reversible receptacle  326  is typically rigidly joined to body  325  of reversible USB appliance  324 . USB device  320  contains a standard USB plug  322 , which is to be coupled with reversible USB receptacle  326 . Appliance  324  allows the coupling of USB device  320  in two coupling orientation, thus creating the same advantageous effect of alternate coupling as has been described in reference to  FIGS. 9   a - 9   h.    
   It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art which would occur to persons skilled in the art upon reading the foregoing description.