Abstract:
A DSL modem ( 50 ). The DSL modem comprises a connector ( 62 ) comprising a first pair of conductors (IP 1 , IP 2 ) and a second pair of conductors (OP 1 , OP 2 ). The DSL modem further comprises both circuitry for transmitting according to a DSL protocol ( 52 ) and circuitry for receiving according to a DSL protocol ( 52 ). Still further, the DSL modem comprises switching circuitry ( 60 ) operable to selectively switch to a first position to couple the circuitry for transmitting and the circuitry for receiving to the first pair of conductors and to a second position to couple the circuitry for transmitting and the circuitry for receiving to the second pair of conductors. Lastly, the DSL modem comprises circuitry ( 52,  CONTROL) for controlling the switching circuitry to switch to one of the first position and the second position and for then detecting whether DSL service exists along the pair of conductors to which the circuitry for transmitting and the circuitry for receiving is then coupled.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
         [0001]    Not Applicable.  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable.  
         BACKGROUND OF THE INVENTION  
         [0003]    The present embodiments relate to digital subscriber line (“DSL”) technology, and are more particularly directed to a DSL modem operable to efficiently connect to DSL services in existing telephone service connectors.  
           [0004]    The exchange of digital information between remotely located computers is now a pervasive part of modem computing and occurs in all sorts of computer contexts including business, education, and personal use. Such uses by all current predictions appear to be even more desirable in the future. Video on demand (“VOD”) is one area which has for some time driven the advancement of technology in this area. More recently, the rapid increase in use and popularity of the Global Internet hereafter, the “Internet”) has perhaps surpassed the excitement created by VOD.  
           [0005]    One type of technology arising from the above and continuing to evolve is referred to in the art as digital subscriber line or DSL. DSL is a public network technology that delivers relatively high bandwidth over conventional telephone company copper wiring at limited distances. DSL has been further separated into several different categories, where the differing DSL categories are currently developing, some at different rates than others. This evolution prevents an absolute definition of certain DSL categories, but some observations may be made at the current time. Generally with respect to the various DSL technology categories, each differs in some respects while each also shares some similarities. As to differences of the DSL categories, they may diverge in one or more of the expected data transfer rate, the medium type and length over which data are communicated, and the scheme for encoding and decoding data for communication. As to the similarities of the DSL technologies, generally speaking each DSL system is provisioned into modem pairs. One modem of the modem pair is located at a customer site. The other modem of the modem pair is located at the site of an owner, or controller, of a twisted conductor pair network. Currently, the most evident owner or controller is a telephone company central office. Within the telephone company system, its modem is connected to communicate with some type of network, often referred to as a backbone network. The backbone network is further coupled in a network manner to provide other communication paths to and from the backbone network. Given its network nature, the backbone network may further communicate with other information sources and, most notably under current technology, with the Internet. Thus, information accessible to the backbone network, such as Internet information, may be communicated between the central office DSL modem and a customer site with its own compatible DSL modem. Within this general system, it is also anticipated that data rates between DSL modems may be far greater than current voice modem rates. Indeed, current DSL systems being tested or projected range in rates on the order of 500 Kbps to 18 Mbps, or even faster. The higher rates for some DSL systems are only for so-called downstream communications, that is, from the central office to the customer site; thus, for those systems, communication in the other direction (i.e., upstream from the customer site to the central office) is generally at a rate considerably lower than the downstream rate. Lastly, note that most DSL technologies do not use the whole bandwidth of the twisted wire pair, and they often reserve low bandwidth for a voice channel. As a result, while a line is being used by a DSL system, the same line may concurrently communicate a voice conversation as well.  
           [0006]    Briefly looking at perhaps the most publicized DSL technology currently being developed, it is referred to as Asymmetric Digital Subscriber Line, or “ADSL.” ADSL has been standardized by ANSI as seen by its T 1 . 413  standard. However, even given that standard, there continues to be debate and competition as to whether devices complying with the standard provide promise for future wide scale use, and indeed whether the standard requires revision. For example, the standard currently contemplates a modulation technology called Discrete Multitone (DMT) for the transmission of high speed data, but more recently it has been urged that the standard further include an alternative data transmission technique referred to as carrierless amplitude/phase modulation (CAP). In any event, given the state of the art discussion of ADSL systems, it is contemplated that they will communicate over a single copper twisted wire pair, and provide downstream rates on the order of 1.5 Mbps to 9 Mbps, while upstream bandwidth will range from 16 kbps to 1 Mbps. Along with Internet access, telephone companies are considering delivering remote local area network (“LAN”) access and VOD services via ADSL.  
           [0007]    As to other DSL categories being developed, they include High-Bit-Rate Digital Subscriber Line (“HDSL”), Symmetrical Digital Subscriber Line (“SDSL”), and Very-high-data-rate Digital Subscriber Line (“VDSL”). HDSL, unlike ADSL as described above, has a symmetric data transfer rate, that is, it communicates at the same speed in both the upstream and downstream directions. Current perceived speeds are on the order of 1.544 Mbps of bandwidth, but require two copper twisted wire pairs. HDSL&#39;s operating range is more limited than that of ADSL, and is currently considered to be effective at distances of approximately 12,000 feet. Beyond such a distance, HDSL communication requires signal repeaters to extend the service. SDSL delivers a comparable speed and also a symmetric data transfer as compared to HDSL, but achieves these results with a single copper twisted wire pair. However, the operating range of an SDSL system is limited to approximately 10,000 feet. Lastly, VDSL provides asymmetric data transfer rates, but anticipates much higher speeds than those competing DSL technologies described above. Currently, rates over a single twisted copper pair on the order of 13 Mbps to 52 Mpbs downstream, and 1.5 Mbps to 2.3 Mbps upstream, are contemplated. Note, however, that such rates are expected to operate only over a range of 1,000 to 4,500 feet.  
           [0008]    Having introduced DSL technology, attention is now directed to the implementation of that technology at the consumer level. Under the current and typical scenario, when a consumer wants DSL capability in his or her computer, the consumer contacts a DSL provider (e.g., the local telephone company). The DSL provider then sends a representative to the location specified by the consumer and connects a DSL modem to the consumer&#39;s computer. More particularly under contemporary implementations, an external DSL modem is connected to the consumer&#39;s computer, such as by coupling the external DSL modem to a network interface card (“NIC”) located internally within the computer. Alternative couplings also may be used or are currently being developed (e.g., use of the Universal Serial Bus (“USB”)). The DSL modem is also then coupled to the telephone wiring in the location of the computer, such as to the well-known RJ 11  connectors used in business and residential locations for voice telephones. Further, the installation also may involve some additional wiring at the outside of the home or business, that is, where the telephone company&#39;s wiring connects to the location (e.g., via a network interface device (“NID”)) as is further explored later. In any event, at the present time an installation of a DSL modem commonly requires a person, such as a telephone company representative, who has a considerable level of technical expertise.  
           [0009]    Recalling from above that a DSL modem is typically connected to an RJ 11  connector in a home or business, the present embodiments are directed to increasing the chance of proper signal communications when this connection is made. Specifically, an RJ 11  connector, as known in the art, includes six cavities aligned in a row, where a conducting pin may be placed within each such cavity; in the majority of home applications, the two outermost of these six cavities are left empty, while the remaining four cavities between those outermost cavities each retain a corresponding conductor pin. Unless stated otherwise, for the sake of a consistent example for the remainder of this document the example of four pins used in the RJ 11  connector are described. Thus, in both the RJ 11  female receptacle and male plug, these four pins are aligned in a row. The two pins at the ends of the row are referred to in the art as an outer pair, whereas the two pins located along the row and between the outer pair are referred to in the art as the inner pair. Further, a typical voice telephone cable includes two twisted wire pairs of conductors. Often, to support a single telephone line in a home or business and according to the known “plain ordinary telephone service” (“POTS”), one twisted wire pair of the telephone cable is connected to the inner pair pins of the RJ 11  connector, while the outer pair pins of the RJ 11  connector are not further connected to any conductors of the telephone cable. However, once a DSL modem is contemplated as also being connected to the RJ 11  connector, there arises the issue of whether to use the outer pair pins to communicate with the DSL modem, or to further re-arrange the connections to use the inner pair pins to communicate with the DSL modem and then the outer pair pins to communicate with a telephone. Further complicating the possibilities is the fact that filtering is also typically required once a DSL modem is to be supported along with a voice telephone device. By way of further background to these considerations, FIGS. 1 through 3 discussed below depict various contemporary alternative connections of an ADSL modem to an RJ 11  connector.  
           [0010]    [0010]FIG. 1 illustrates a first prior art telephone/DSL modem wiring system designated generally at  10 . System  10  includes a twisted wire pair TP 1  of conductors provided by the telephone company (“TELCO”) and connected to a network interface device (“NID”)  12 . For example, NID  12  is typically enclosed in a box attached to or proximate to the outside of a residential home or business. From NID  12 , twisted wire pair TP 1  is connected directly to the inner pair of pins IPP 1  of an RJ 11  receptacle RJ 11   1 . Receptacle RJ 11   1  is for connecting to an ADSL modem, that is, an RJ 11  plug (not shown) on or connected to an ADSL modem may be inserted within RJ 11  receptacle RJ 11   1  to thereby couple the modem to communicate with the TELCO (i.e., with a corresponding modem at the TELCO). Additionally, note that the outer pair of pins OPP 1  of RJ 11  receptacle RJ 11   1  are electrically floating. Returning to twisted wire pair TP 1  in NID  12 , it also is connected to an input of a low pass filter (“LPF”)  14 , where LPF  14  permits only signals in the POTS frequency to pass, such as those on the order of 4 KHz or less. The output of LPF  14  is connected to the inner pair of pins IPP 2  of an RJ 11  receptacle RJ 11   2 . Receptacle RJ 11   2  is for connecting to a POTS telephone, or other device, such as an answering machine or voice modem, operable to communicate along a POTS medium. Specifically, this connection is typically made by inserting an RJ 11  plug (not shown) on or connected to the POTS telephone device into RJ 11  receptacle RJ 11   2  to thereby couple the POTS telephone device to communicate with the TELCO. Lastly, note that the outer pair of pins OPP 2  of RJ 11  receptacle RJ 11   2  are electrically floating.  
           [0011]    The operation of system  10  is now explored. In general, the TELCO provides both POTS and DSL modem communications via twisted wire pair TP 1  to NID  12 . With respect to DSL modem communications, they are achieved via the direct connection to receptacle RJ 11   1 . Thus, so long as the ADSL modem is connected to inner pins IPP 1  of receptacle RJ 11   1 , any appropriate DSL signal may be communicated between the ADSL modem and twisted wire pair TP 1 . With respect to the POTS communications, they are filtered by LPF  14  and pass to receptacle RJ 11   2 . As a result, note that any relatively high frequency signals (i.e., greater than 4 KHz) on twisted wire pair TP 1  do not reach receptacle RJ 11   2  and, hence, do not reach any POTS telephone device connected to that receptacle. Such filtering is typically required because current POTS devices do not have a defined frequency response for these relatively high frequency signals. Further, LPF  14  thereby eliminates any possibility that operation of the POTS telephone connected to receptacle RJ 11   2  would then affect the operation of an ADSL modem that is directly-connected to twisted wire pair TP 1  via receptacle RJ 11   1 . In any event, so long as the POTS telephone device is connected to inner pins IPP 2  of receptacle RJ 11   2 , any appropriate POTS signal may be communicated between the POTS telephone device and twisted wire pair TP 1 .  
           [0012]    While the preceding discussion of system  10  in FIG. 1 demonstrates a straightforward manner of connecting both an ADSL modem and a POTS telephone device to a TELCO twisted wire pair TP 1 , various drawbacks also may be observed with respect to system  10 . As one drawback, the consumer using system  10  must be aware of the limitation that receptacle RJ 11   1  is for connecting to an ADSL modem and receptacle RJ 11   2  is for connecting to a POTS telephone device. In other words, if the consumer were to reverse these connections, then a POTS telephone device connected to receptacle RJ 11   1  may not properly communicate due to the receipt of relatively high frequency signals, and an ADSL modem connected to receptacle RJ 11   2  would not properly communicate because it would only receive relatively low frequency signals. As another drawback, system  10  operates properly only if both the ADSL modem and the POTS telephone device are configured to communicate along the inner pair of pins of an RJ 11  configuration. For a POTS telephone device, this configuration may be likely because many such devices are hard-wired to communicate only along such inner pair pins. However, given the already-expanding competition and development of ADSL technology, some manufacturers may consider providing their ADSL modems with a connection to the outer pair of RJ 11  pins rather than the inner pair, such as for reasons further demonstrated below. If such an alternative ADSL modem were connected to receptacle RJ 11   1 , then it would not communicate at all given that outer pins OPP 1  of receptacle RJ 11   1  are electrically floating.  
           [0013]    [0013]FIG. 2 illustrates a second prior art telephone/DSL modem wiring system designated generally at  20 , and which shares some general aspects with system  10  described above. System  20  includes a twisted wire pair TP 2  provided by the TELCO and connected to an NID  22 . From NID  22 , twisted wire pair TP 2  is connected directly to the outer pair of pins OPP 3  of an RJ 11  receptacle RJ 11   3 . For reasons more clear below, RJ 11  receptacle RJ 11   3  is for connecting to either an ADSL modem or a POTS telephone device. Additionally, twisted wire pair TP 2  in NID  22  is connected to an input of an LPF  24 , where LPF  24  operates in the same manner as LPF  14  of FIG. 1, thereby permitting only signals in the POTS frequency to pass. The output of LPF  24  is connected to the inner pair of pins IPP 3  of RJ 11  receptacle RJ 11   3 . Given the preceding connections, note that the connection to inner pair IPP 3  and outer pair OPP 3  may be achieved using a single POTS cable as shown at CB, thereby including two twisted wire pairs between NID  22  and RJ 11  receptacle RJ 11   3 .  
           [0014]    The operation of system  20  is as follows. The TELCO provides both POTS and DSL modem communications via twisted wire pair TP 2  to NID  22 . With respect to DSL modem communications, they are achieved via the direct connection from NID  22  to outer pins OPP 3  of receptacle RJ 11   3 . Thus, an ADSL modem may be connected via an RJ 11  plug to receptacle RJ 11   3  and thereby properly communicate ADSL communications with the TELCO so long as the ADSL modem is connected to outer pins OPP 3  of receptacle RJ 11   3  rather than to inner pins IPP 3  of receptacle RJ 11   3 . Conversely, with respect to the POTS communications, they are achieved via the filtered connection to inner pins IPP 3  of receptacle RJ 11   3 . Thus the POTS telephone device may be connected via an RJ 11  plug to RJ 11  receptacle RJ 11   3  and may properly communicate POTS communications with the TELCO so long as the POTS telephone device is connected to inner pins IPP 3  of receptacle RJ 11   3  rather than to outer pins OPP 3  of receptacle RJ 11   3 .  
           [0015]    While the preceding discussion of system  20  in FIG. 2 demonstrates that system  20  supports either an ADSL modem or a POTS telephone communication from receptacle RJ 11   3 , various drawbacks also may be observed with respect to system  20 . As one drawback, system  20  operates properly only if the ADSL modem is configured to communicate along the outer pair of pins of an RJ 11  configuration and the POTS telephone device is configured to communicate along the inner pair of pins of an RJ 11  configuration. Again, given the diverse number of ADSL modems being or to be implemented, there is no assurance that this constraint will be met. As another drawback, for proper operation of both the ADSL modem and the POTS telephone device, system  20  requires that the person who implements its wiring properly terminate each of the four wires at the correct one of either an inner or outer pin; clearly, various reasons may cause an error in such wiring to occur.  
           [0016]    [0016]FIG. 3 illustrates a third prior art telephone/DSL modem wiring system designated generally at  30 . System  30  shares some electrical-connection aspects with system  10  described above while the physical locations of various connections differ in some respects. Turning to system  30 , it includes a twisted wire pair TP 3  provided by the TELCO and connected to an NID  32 . For system  30 , however, and as further appreciated below, no additional change is made to NID  32  (e.g., such as a filter) to accommodate an ADSL modem at the home or business corresponding to NID  32 . Instead, twisted wire pair TP 3  is connected directly to the inner pair IPP 4  of pins of an RJ 11  receptacle RJ 11   4 . In other words, the connection between NID  32  and RJ 11  receptacle RJ 11   4  is the same as is typically installed to support standard POTS telephone services. However, to further support both POTS telephone service as well as ADSL communications, system  30  further includes a microfilter  34 . Microfilter  34  may be physically presented as a relatively small housing, formed of a rigid material such as plastic, and on the order of two to four inches or less in each of its dimensions. Further, as appreciated from the following description of the electrical connections of microfilter  34 , it is configured to be placed in-line between RJ 11  receptacle RJ 11   4  and either an ADSL modem or a POTS telephone device.  
           [0017]    Looking in detail to the electrical attributes of microfilter  34 , it includes an RJ 11  plug RJ 11   5  which is physically shaped to be fitted into RJ 11  receptacle RJ 11   4  as is known in the art. The inner pins IPP 5  of RJ 11  plug RJ 11   5  are connected to a twisted wire pair TP 4 . Twisted wire pair TP 4  is connected, within microfilter  34 , directly to the outer pair of pins OPP 6  of an RJ 11  receptacle RJ 11   6 . Additionally, twisted wire pair TP 4  is connected, within microfilter  34 , to the input of an LPF  36 , and an output twisted wire pair TP 5  from LPF  36  is connected to the inner pair of pins IPP 6  of RJ 11  receptacle RJ 11   6 . Lastly, either an ADSL modem or a POTS telephone device may be connected to RJ 11  receptacle RJ 11   6 , where such connection may be made by inserting an RJ 11  plug (not shown) from either the modem or telephone device into RJ 11  receptacle RJ 11   6 . To ensure a proper ADSL communication path, the RJ 11  plug of the ADSL modem must communicate along its outer pins to contact and communicate with outer pair of pins OPP 6  of RJ 11  receptacle RJ 11   6 . Conversely, to ensure a proper POTS telephone communication path, the RJ 11  plug of the POTS telephone device must communicate along its inner pins to contact and communicate with inner pair of pins IPP 6  of RJ 11  receptacle RJ 11   6 . Lastly, while only a single microfilter  34  is shown in system  30 , one skilled in the art will recognize that for each RJ 11  receptacle wired in the same manner as RJ 11  receptacle RJ 11   4 , a corresponding microfilter wired in the same manner as microfilter  34  may be connected to the RJ 11  receptacle, and in which case either an ADSL modem or a POTS telephone device may be connected to the microfilter in the same manner as described with respect to microfilter  34 . In this latter instance of multiple microfilters, note that under contemporary systems only one of those microfilters should connect to an ADSL modem while the remaining microfilters may connect to POTS telephone devices; this arises from the aspect that under contemporary configurations only a single ADSL modem is generally supported for a single copper pair (i.e., at the site of that copper pair), primarily due to the lack of the ability to share frequencies and negotiate a connection between multiple ADSL modems connected at a single copper pair.  
           [0018]    While system  30  of FIG. 3 supports both ADSL modem and POTS telephone communications, it too has drawbacks. For example, different types of microfilters may use different sets of inner or outer pins for either ADSL or POTS telephone service and, thus, a modem or telephone device connected to the microfilter must be configured to communicate using the appropriate corresponding pins. As another example, the microfilter represents a separate piece of equipment that the user must obtain.  
           [0019]    As yet further background, the prior art further includes some DSL modems which include a mechanical switch typically attached to a circuit board included within the DSL modem. The mechanical switch is intended for use by a technically-savvy person so that such a person may move the switch to one of two positions, where in a first position the DSL modem is connected to communicate along the inner pair of pins of its RJ 11  connector while in a second position the DSL modem is connected to communicate along the outer pair of pins of its RJ 11  connector. The movement of this switch, however, is purely manual an is not further facilitated by the modem itself; instead, the person operating the switch is somehow left to independently determine the proper location of the switch in an effort to achieve a proper DSL communication path.  
           [0020]    In addition to the preceding, the present inventor has recognized additional observations particularly in view of the developing marketplace. For example, given the level of DSL developments, there is also an increasing need to present DSL technology to the general public in as straightforward a manner as possible. Indeed, it is contemplated that consumers will someday seek to implement DSL modems in a manner at least as straightforward as now used for telephone devices and voice modems. Such an approach may bring a consumer to a local electronics store or otherwise permit the consumer to obtain a DSL modem from some alternative source, where the consumer thereafter desires to couple the modem to his or her computer without the assistance of a technically-educated service representative. However, the many alternatives provided above demonstrate that such a consumer is very unlikely to understand the technical considerations involved or necessary to achieve the specific DSL modem connections in their home or office. Also shown above are various factors that may result in an inoperable installation by a consumer. Thus, to facilitate this type of self-installation, there is a need to simplify the process so as to increase the chances that the installation will operate properly, as is achieved by the present embodiments.  
         BRIEF SUMMARY OF THE INVENTION  
         [0021]    In the preferred embodiment, there is a DSL modem. The DSL modem comprises a connector comprising a first pair of conductors and a second pair of conductors. The DSL modem further comprises both circuitry for transmitting according to a DSL protocol and circuitry for receiving according to a DSL protocol. Still further, the DSL modem comprises switching circuitry operable to selectively switch to a first position to couple the circuitry for transmitting and the circuitry for receiving to the first pair of conductors and to a second position to couple the circuitry for transmitting and the circuitry for receiving to the second pair of conductors. Lastly, the DSL modem comprises circuitry for controlling the switching circuitry to switch to one of the first position and the second position and for then detecting whether DSL service exists along the pair of conductors to which the circuitry for transmitting and the circuitry for receiving is then coupled. Other circuits, systems, and methods are also disclosed and claimed.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0022]    [0022]FIG. 1 illustrates a prior art electrical diagram for coupling an ADSL modem to the inner pair of conductors in a first dedicated RJ 11  receptacle and for coupling a POTS telephone device to the inner pair of conductors in a second dedicated RJ 11  receptacle.  
         [0023]    [0023]FIG. 2 illustrates a prior art electrical diagram for coupling either an ADSL modem to the outer pair of conductors in an RJ 11  receptacle or for coupling a POTS telephone device to the inner pair of conductors in the RJ 11  receptacle.  
         [0024]    [0024]FIG. 3 illustrates a prior art electrical diagram for coupling either an ADSL modem to the outer pair of conductors in an in-line microfilter RJ 11  receptacle or for coupling a POTS telephone device to the inner pair of conductors in the in-line microfilter RJ 11  receptacle.  
         [0025]    [0025]FIG. 4 illustrates a system having a remote computer and a telephone office computer, where each computer is coupled to a modem in which the present inventive embodiments may be implemented.  
         [0026]    [0026]FIG. 5 illustrates a block diagram of a DSL modem according to the preferred embodiment.  
         [0027]    [0027]FIG. 6 illustrates an electrical diagram of service select switch  60  and RJ 11  receptacle  62  from FIG. 5 in greater detail.  
         [0028]    [0028]FIG. 7 illustrates a flow chart of a method of operation of the preferred modem and particularly with respect to its service select switch for automatically detecting and establishing a DSL communication path between the modem and the TELCO.  
         [0029]    [0029]FIG. 8 illustrates a flow chart of an alternative method of operation of the preferred modem whereby the modem is operable to establish a voice modem communication path in response to detecting that DSL service is unavailable.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]    [0030]FIGS. 1 through 3 were described in the preceding Background Of The Invention section of this document and the reader is assumed to be familiar with that discussion.  
         [0031]    [0031]FIG. 4 illustrates a system  40  depicting by way of example the context in which the present inventive embodiments may be implemented. By way of example, system  40  includes aspects which relate to two different geographic locations, one being a telephone company central office and the other being a location remote from that office. For purposes of appreciating a common example, the remote location may be a home or office of a user in that location while the central office may be any of those types of offices included in a telephone company system. These two locations may be fairly dose together, or vast distances apart, yet they both may benefit from the present embodiments. These benefits as well as the details of the inventive embodiments are presented below.  
         [0032]    At a minimum for illustrating the preferred embodiments, each of the central office and the remote location houses a computer  42  and  44 , respectively. Computers  42  and  44  may be of any type of known computer configurations and, indeed, the type of computing device at the remote location may well differ from the type or configuration of that used at the central office (e.g., a rack system). Typically, a user of either computer may provide input to a corresponding computer, such as by way of a keyboard K and a mouse MS or other input or pointing device as known in the art. To simplify the present illustration, note for purposes of FIG. 4 that each of the reference identifiers for these items (i.e., K and MS) as well as for other items discussed below further includes a subscript reciting the reference number of the corresponding computer. For example, computer  42  includes keyboard K 42  and mouse MS 42 . Continuing with this convention and looking to other attributes of computers  42  and  44 , each computer preferably includes some device for presenting output to a user, such as a display D in the case of FIG. 4. Internally to each computer may be various circuits including those mounted on circuit boards and/or cards, including a motherboard (shown in phantom) which includes a memory MEM, a central processing unit CPU or more than one such CPU as may likely be the case for host computer  44 , and likely other circuitry (not shown). Of particular note to the present embodiments, also coupled to each computer is a DSL modem M so that each of computers  42  and  44  may communicate with one another over a standard telephone company distribution system. The coupling between a DSL modem M and its respective computer  42  or  44  may be achieved in various manners, such as via a network interface card (“NIC”) or some other bus connection (e.g., USB). Indeed, it is also contemplated that DSL modems may be implemented as internal modems configured in the manner of a computer card. Further, in the case of computer  42  at the telephone company, note that it is likely to actually support multiple DSL modems, although only one is shown to simplify the illustration as well as the following discussion. Looking to the distribution system along which the modems communicate, it includes twisted conductor pairs accessible for a connection between computers  42  and  44 . In this regard, DSL modem M 44  of computer  44  provides an output which is provided to a standard telephone connector (e.g., RJ 11 ) or other applicable connector and, thus, is connected to a telephone wall outlet O 44 , having such a connector, via a standard telephone communication cable C 44 . This connection permits communication from DSL modem M 44  over the telephone company distribution system and, therefore, with DSL modem M 42  of computer  42 . Note that while comparable connections using cable C 42  and outlet O 42  are shown at the telephone company, more typical industrial type connections may actually exist at that end of the connection. Lastly, given the communications of DSL modems M 42  and M 44  with one another, note that in the preferred embodiment such communications are by way of ADSL communications. Such communications may be preferred for various reasons. For example, ADSL communications are growing in popularity and, thus, are likely to be favored in the consumer marketplace. As another example, the preferred embodiment uses part of the ADSL protocol, as detailed later, to support a method of coupling each modem to a corresponding receptacle in a manner that increases the likelihood of a proper connection. Despite these advantages and preferences, however, one skilled in the art will appreciate that many of the present teachings also provide aspects and benefits which may be implemented in other DSL modem categories.  
         [0033]    Given system  40  of FIG. 4, it is intended that its components are used within the present inventive scope to accomplish DSL communications between modems M 42  and M 44 . In this regard, note that computer  42  is connected via an appropriate interface I/F to a backbone network. This network may be of various types, with Ethernet being a popular contemporary example. As a result, computer  42  may communicate with any other device or resource which also is coupled to communicate with the backbone network. Indeed, as one example, FIG. 4 illustrates that the Internet is also coupled to the backbone network through some kind of networking architecture. Consequently, computer  42  may communicate, via the backbone network, with the Internet. Additionally, due to the modem-to-modem communication path between computers  42  and  44 , computer  44  may use DSL communications for accessing other media available to computer  42  at the telephone company central office, including the Internet.  
         [0034]    [0034]FIG. 5 illustrates a block diagram of a DSL modem  50  serving as the preferred embodiment for forming modems M 42  and M 44 , with it understood that a modem at each site may include some different circuitry based on whether the site is at the service provider or is at a remote modem (e.g., a remote modem such as modem M 44  may further include certain circuitry for timing recovery while such circuitry is not included on a central office modem such as modem M 42 ). Turning now to the specific illustration of FIG. 5, modem  50  includes a data pump  52  for performing various DSL data processing and related functions for modem  50 . By way of example, data pump  52  may be implemented using a digital signal processor (“DSP”) or more than one DSP. For example, such devices are sold in various forms by Texas Instruments Incorporated. Data pump  52  also preferably includes data storage capability to store both modem data as well as program code to provide programming functionality to data pump  52 . By way of example, such programming may include a DSL algorithm for communicating data according to a DMT algorithm. Finally, note that data pump  52  also may support voice modem capabilities.  
         [0035]    Looking to the left of FIG. 5, modem  50  includes a bidirectional bus B to couple modem  50  to a computer, such as to one of computers  42  and  44 . Bus B may take various forms depending on the manner in which the protocol between the modem and computer is supported, such as through an Ethernet connection, an industry standard architecture (“ISA”) bus, or via USB. Further in this regard, bus B is bidirectionally coupled to a host interface circuit  54 , where host interface circuit  54  is bidirectionally coupled to data pump  52 . Host interface circuit  54  includes circuitry for supporting the implemented protocol, and also may include various other supporting circuits such as temporary data storage (e.g., one or more buffers, such as FIFOs), registers for communicating protocol commands and status information, interrupt circuitry, data routing circuitry, timing circuitry, and so forth as will be ascertainable by one skilled in the art.  
         [0036]    Concluding FIG. 5, modem  50  includes two analog front end (“AFE”) circuits, namely, a DSL AFE  56  and an optional voice AFE  58 , both of which are bidirectionally connected to both data pump  52  and, via a pair of conductors, to a service select switch  60 . DSL AFE  56  and voice AFE  58  may be constructed according to various designs ascertainable by one skilled in the art. For example, the circuitry of DSL AFE  56  depends on the preferred DSL type being implemented, such as ADSL in the preferred embodiment, and it includes sufficient circuitry to accommodate the DSL communications such as analog-to-digital and digital-to-analog conversion capabilities. As another example, the circuitry of voice AFE  58  may implement a standard voice modem protocol such as the V.90 protocol known in the voice modem art. Service select switch  60  is constructed as detailed later, and is controlled by data pump  52  via a CONTROL bus. Lastly, service select switch  60  is bidirectionally connected to the four conducting pins of an RJ 11  receptacle (or comparable connector) designated generally at  62 . RJ 11  receptacle  62  is for connecting to the TELCO signal, such as by way of a standard RJ 11  cable used for connecting to an RJ 11  receptacle in a home or business. Further and for reasons detailed later, this connection also may include an in-line microfilter or other connection, where the operation of service select switch  60  increases the likelihood of a proper DSL communication path being established despite the various different pin configurations of the connector to which RJ 11  receptacle  62  is coupled.  
         [0037]    [0037]FIG. 6 illustrates an electrical diagram of service select switch  60  and RJ 11  receptacle  62 , both from FIG. 5, in greater detail. Turning first to service select switch  60 , it includes a switch  64  which, in the illustrated embodiment, is an electromechanical switch, that is, it has a mechanical movement which is controlled in response to an electronic signal. Switch  64  includes two poles P 1  and P 2 . Each of poles P 1  and P 2  is connected to a respective conductor CR 1  and CR 2 , where conductors C 1  and C 2  are connected to both DSL AFE  56  and voice AFE  58  (see FIG. 5). Pole P 1  may be switched to either a terminal T 1  or a terminal T 2 , while concurrently pole P 2  may be switched to either a terminal T 3  or a terminal T 4 . More particularly, the concurrent switching in this regard is in response to assertion of the CONTROL signal along the CONTROL bus from data pump  52 , as further detailed later. Terminals T 1  and T 3  are connected to the outer pins of RJ 11  receptacle  62  and, more particularly, terminal T 1  is connected to outer pin OP 1  while terminal T 3  is connected to outer pin OP 2 . Terminals T 2  and T 4  are connected to the inner pins of RJ 11  receptacle  62  and, more particularly, terminal T 2  is connected to inner pin IP 1  while terminal T 4  is connected to inner pin IP 2 .  
         [0038]    The operation of service select switch  60  and RJ 11  receptacle  62  from FIGS. 5 and 6 is now described with further reference to a method  70  shown in FIG. 7. Method  70  begins with a start step  72 , where step  72  may be reached in various manners. For example, in one embodiment, step  72  may commence when power is supplied to modem  50  or during system start-up. As another example, a reset button or the like may be provided in connection with modem  50  where a consumer may depress the button to cause step  72  to be reached. As yet another example, a software link could be provided to cause step  72  to be reached. Lastly, in start step  72  a COUNT value is initialized, such as by setting it equal to a value of one. After start step  72 , method  70  continues to step  74 .  
         [0039]    In step  74 , modem  50  communicates a known DSL protocol signal, from data pump  52  to DSL AFE  56  and along conductors CR 1  and CR 2 , to service select switch  60 . The particular DSL protocol signal is preferably one in which a known response is expected from the TELCO. For example, under the G. 994 . 1  handshake procedures for ADSL transceivers, the known DSL protocol signal communicated by step  74  may be an R-TONES-REQ signal. Further, in the preferred embodiment, service select switch  60  defaults in a first instance to a known position for switch  64 ; for example, assume for this first instance that switch  64  is in the upward position as shown in FIG. 6. Due to this switch position, the R-TONES-REQ signal is communicated from DSL AFE  56 , via conductors CR 1  and CR 2 , to terminals T 1  and T 3 . Further, due to the connection of terminals T 1  and T 3  to RJ 11  receptacle  62 , then the R-TONES-REQ signal is therefore communicated to the outer pins (i.e., OP 1  and OP 2 , respectively) of RJ 11  receptacle  62 . By way of introduction to later steps, therefore, note that if these outer pins are connected to the TELCO, then the R-TONES-REQ signal is thereby communicated to the TELCO. Next, method  70  continues from step  74  to step  76 .  
         [0040]    In step  76 , data pump  52  analyzes the data, if any, received by the same pins along which the protocol was communicated in the immediately-preceding instance of step  74 . Particularly, the step  76  analysis determines if an appropriate protocol response is communicated back from the TELCO. In other words, step  76  determines whether a DSL response was received at RJ 11  receptacle  62  by the same pair of conductors along which the step  74  DSL communication was sent. For example, when the R-TONES-REQ signal was communicated by step  74  to outer pins OP 1  and OP 2  of RJ 11  receptacle  62 , then step  76  determines if a C-TONES signal is received back along those outer pins OP 1  and OP 2  of RJ 11  receptacle  62 . Note that this determination may be made by data pump  52  in response to the signals at conductors CR 1  and CR 2  via DSL AFE  56 . If an appropriate protocol response is received, method  70  continues from step  76  to step  78 . In contrast, step  76  will await the appropriate protocol response for a timeout period (e.g., ten seconds), and if the appropriate protocol response is not received along the current pair of pins of RJ 11  receptacle  62  (e.g., outer pins OP 1  and OP 2  for the first instance), then method  70  continues from step  76  to step  80 .  
         [0041]    In step  80 , data pump  52  asserts the CONTROL signal along the CONTROL bus to service select switch  60 , thereby causing switch  64  to toggle its position. Accordingly, maintaining the preceding example where switch  64  was initially in its upward position as shown in FIG. 5, then upon a first instance of step  80 , the asserted CONTROL signal toggles switch  64  downward. In response, therefore, pole P 1  is connected to T 2  while pole P 2  is connected to terminal T 4 . Consequently, at this point conductors CR 1  and CR 2  are electrically connected to inner pins IP 1  and IP 2 , respectively, of RJ 11  receptacle  62 . Additionally, step  80  increments the COUNT value. Next, method  70  continues from step  80  to step  82 .  
         [0042]    In step  82 , data pump  52  determines whether the COUNT value has exceeded a threshold value. As more apparent following the conclusion of the discussion of method  70 , by incrementing the value of COUNT in the preceding step  80 , there is an indication of the number of times that switch  64  is toggled. This COUNT value therefore also corresponds to repeated instances where step  74  transmitted a DSL protocol signal (e.g., R-TONES-REQ) and the appropriate response was not received. Accordingly, if this event has occurred a relatively large number of times (e.g., ten), then it may be likely concluded that no DSL service is available and desirable to discontinue any additional efforts to transmit the DSL protocol and receive a response. Indeed, if switch  64  is implemented as an electromechanical switch, then the act of toggling it numerous times may result in an undesirable audible chatter. In any event, therefore, the threshold of step  82  is set to the desired relatively large number, and if this threshold is exceeded, method  70  continues from step  82  to step  84 . Conversely, if the threshold is not exceeded, then method  70  returns from step  82  to step  74 . Both of these alternative paths are discussed immediately below.  
         [0043]    In step  84 , having been reached because the COUNT value exceeds the step  82  threshold, then a notification is issued to the user of modem  50  that DSL service is not available at the receptacle to which the modem has been connected (assuming that such a physical connection has occurred). The notification may be provided in various manners. For example, data pump  52  may provide a notification via a software link to the computer coupled to modem  50 , and the computer may respond with either or both of a display warning or an audible warning. Alternatively, some type of notification element may be physically incorporated within modem  50 , such as a light or audible device so as to notify the user that the modem was incapable of detecting a DSL service on either pair of pins of RJ 11  receptacle  62 .  
         [0044]    Looking now to the instance of a return to step  74  following step  82 , modem  50  again communicates the known DSL protocol signal from data pump  52  to service select switch  60 . At this point, however, and due to the previous operation of step  80 , the present communication of the known DSL protocol signal will be an instance wherein switch  64  has been toggled to the opposite location of that from previous first instance of step  74 . Thus, for the second instance of step  74 , the known DSL protocol signal is connected to a different pair of pins in RJ 11  receptacle  62  as compared to the first instance of step  74 , and in the present example, this second instance communicates the known DSL protocol signal to inner pins IP 1  and IP 2  of RJ 11  receptacle  62 . Following this second instance of step  74 , again method  70  continues to step  76 .  
         [0045]    When step  76  is reached after the second instance of step  74 , data pump  52  now analyzes the data, if any, received by the same pins along which the DSL protocol was communicated by the second instance of step  74 . In other words, because the DSL protocol in the second instance of step  74  was communicated to inner pins IP 1  and P 2  of RJ 11  receptacle  62 , then the current (i.e., second) instance of step  76  determines if an appropriate protocol response is communicated back from the TELCO along inner pins IP 1  and IP 2  of RJ 11  receptacle  62 . Once more, the flow after step  76  continues in the manner described above, thereby proceeding to step  80  if the proper DSL response is not received, or proceeding to step  78  if a proper DSL response is received.  
         [0046]    From the preceding, one skilled in the art will appreciate that step  78  is reached only if a proper DSL communication is received by a pair of pins of RJ 11  receptacle  62  in response to a DSL request being sent along that same pair of pins. Further, if step  78  is reached, switch  64  is maintained in its then-current position, and additional DSL communications may occur between modem  50  and the TELCO using the current position of switch  64 . In other words, when step  78  is reached, method  70  has automatically detected DSL service availability from the TELCO along the conductive path then-existing due to the position of switch  64 . As a possible addition in the preferred embodiment, the current position of switch  64  may be stored in a memory (e.g., non-volatile memory) either within or outside of data pump  52 , and if method  70  is later restarted (e.g., after a power down and up of modem  50 ) then the stored position may be used to place switch  64  in that stored position for the next instance of steps  74  and  76 .  
         [0047]    Having demonstrated the preferred embodiment and its operation as shown in method  70  of FIG. 6, one skilled in the art may readily appreciate that the preferred embodiment will automatically establish a DSL communication path for each of the alternative prior art wiring configurations in FIGS. 1 through 3, or an appropriate notification will be provided if not DSL service is available. For example with reference to FIG. 1, if modem  50  were connected via a standard twisted pair connector to receptacle RJ 11   1 , then either in response to an initial setting of switch  64  or after a toggling of that setting, DSL service would be detected along inner pin pair IPP, and modem  50  would be connected thereto by switch  64 . Further, if modem  50  were connected via a standard twisted pair connector to receptacle RJ 11   2 , then DSL service would not be detected on either the inner or outer pair of pins for that receptacle, and the user would be informed of the lack of available DSL service. As an example with reference to FIG. 2, if modem  50  were connected via a standard twisted pair connector to receptacle RJ 11   3 , then either in response to an initial setting of switch  64  or after a toggling of that setting, DSL service would be detected along outer pin pair OPP 3  and modem  50  would be connected thereto by switch  64 . Finally with reference to FIG. 3, if modem  50  were connected via a standard twisted pair connector to microfilter  34  (i.e., to its receptacle RJ 11   6 ), then either in response to an initial setting of switch  64  or after a toggling of that setting, DSL service would be detected along outer pin pair OPP 6  and modem  50  would be connected thereto by switch  64 .  
         [0048]    [0048]FIG. 8 illustrates an alternative embodiment of operation of modem  50  and designated generally at  90 . Method  90  includes many of the steps of method  70  from FIG. 7 and, thus, the same reference numerals for those steps are carried forward to FIG. 8. As a modification, however, note that the method flow following an affirmative finding in step  82  is to a new series of steps  92  through  100 . Thus, this modification is invoked in the instance that switch  64  has been toggled back and forth a sufficient number of times such that the COUNT exceeds the threshold of step  82 , and DSL service has not been detected. At this point, method  90  continues to step  92 . Before detailing step  92  and subsequent steps, however, note by way of introduction that the alternative of method  90  further addresses the possibility that while DSL service is not available, the receptacle to which modem  50  has been connected may provide POTS service. This aspect is further appreciated below.  
         [0049]    In step  92 , data pump  52  performs an impedance measurement provided by the pair of pins to which switch  64  is then-connected (i.e., based on whether switch  64  is either in its upward or downward position). In other words, due to the then-current location of switch  64 , the impedance test measures the impedance of the circuitry, if any, coupled externally to RJ 11  receptacle  62 . In the preferred embodiment, the impedance measurement may be made using a selected upstream tone and by evaluating the response to the tone. Following step  92 , method  90  continues to step  94 .  
         [0050]    Step  94  directs further flow in method  90  based on the measured impedance from step  94 . For example, if the result of this measurement indicates a relatively large impedance, then such an indication likely represents an open circuit; thus, this finding is likely representative that the pins of RJ 11  receptacle  62 , from which the impedance measurement was made given the position of switch  64 , are likely not connected to any type of service. In this case, method  90  continues from step  94  to step  96 . Alternatively, if the present pins to which switch  64  are attached are connected to a low pass filter, then the impedance measurement should recognize the impedance of such a filter; further, this finding is likely representative that the pins of RJ 11  receptacle  62 , from which the impedance measurement was made given the position of switch  64 , are likely connected to a low pass filter which is further connected to a POTS service (e.g., such as inner pin pair IPP 2  of RJ 11  receptacle RJ 11   2  in FIG. 1). In this alternative case, method  90  continues from step  94  to step  100 .  
         [0051]    In step  96 , having been reached due to a relatively high impedance measurement in step  94 , data pump  52  asserts the CONTROL signal (along the CONTROL bus) to again cause switch  64  to toggle its position. Thus, with a first impedance measurement having occurred in step  92  for a first position of switch  64 , the operation of step  96  causes switch  64  to move to its other position. Next, method  90  continues from step  96  to step  98 .  
         [0052]    Step  98  operates in the same manner as step  92 , that is, data pump  52  performs an impedance measurement. However, note here that due to the operation of the immediately-preceding step  96 , the impedance measurement of step  98  is for the opposing pair of pins as those involved in step  92 . Thus, step  98  again measures the impedance of the load on RJ 11  receptacle  62 , and again using the same technique described above with respect to step  92  (e.g., using a high frequency tone and the response thereto). Next, method  90  continues from step  98  to step  100 .  
         [0053]    In step  100 , the user is notified in response to the earlier-taken impedance measurements. Specifically, from the preceding one skilled in the art will appreciate that step  100  may be reached either following step  94  in response to an impedance measurement indicating connection of RJ 11  receptacle  62  to a low pass filter, or following step  98  in response to an impedance measurement indicating connection of RJ 11  receptacle  62  to either a low pass filter or to a relatively high impedance (e.g., open circuit). Accordingly, step  100  responds based on these possibilities. Specifically, if step  100  is reached following detection of a low pass filter, then the user is notified that modem  50  is likely connected, via RJ 11  receptacle  62 , to a POTS service. Indeed, recalling now that modem  50  further include a voice AFE  58  and that data pump  52  supports voice modem operatoins, then the user may be given the option to establish a voice modem connection using those pins in RJ 11  receptacle  62  along which the low pass filter was detected. Indeed, as DSL modems become more readily implemented in mobile computers, this option may prove very useful where a computer user in some instances has access to an RJ 11  receptacle supporting DSL service while in other instances has access to an RJ 11  receptacle supporting only POTS service. Alternatively, if step  100  is reached following detection of only a high impedance (on both sets of pins of RJ 11  receptacle  62 ), then the user may be so informed such as by way of display D, an audible tone or message, or both. Lastly, note that method  90  may be further modified where steps  92  and  98  are enhanced to specifically detect a POTS service rather than only measuring impedance. For example, the connections provided via switch  64  may be evaluated to determine if they provide the types of signals provided by a POTS service, where additional hardware may be required on modem  50  to make this type of determination. In any event, if such additional capability is included, then step  100  again may notify the user of the availability of POTS service if such service is detected, and also provide the user the opportunity to establish a voice modem connection thereto.  
         [0054]    From the above, it may be appreciated that the above embodiments provide numerous advantages over the prior art For example, with the improvements to modem  50 , a consumer may connect an RJ 11  receptacle of modem  50 , via a standard RJ 11  cable, to an RJ 11  receptacle in the user&#39;s home or business (or other location), and the modem will automatically detect and provide a communication path to the DSL service if such a service is provided by the home/business RJ 11  receptacle. Further, the operations of automatic detection and connecting should occur regardless of which pair of pins in the home/business RJ 11  receptacle provide the DSL service. As yet another example, the preferred embodiment notifies the consumer if the home/business RJ 11  receptacle does not provide DSL service, and also may notify the user if POTS service is instead provided by that receptacle. Accordingly, from these advantages there is the further advantage that a modem according to the preferred embodiment may properly establish DSL communications by being coupled to one of various different RJ 11  receptacle wiring configurations, including those connected through microfilters. Still further, the preferred embodiments operate to facilitate a DSL connection with a reduced amount of technical understanding by the user, and thereby facilitate a greater penetration into the consumer marketplace. As yet a final advantage of the preferred embodiments, while the present embodiments have been described in detail, various substitutions, modifications or alterations could be made to the descriptions set forth above without departing from the inventive scope. Many examples of such flexibility have been set forth above. Still further examples also exist For example, while service select switch  60  is shown to include a mechanical switch, in an alternative embodiment an electronic switch (e.g., semiconductor and/or transistor based) may be used. As another example, while the preferred embodiment implements an ADSL modem, other DSL modems may benefit from the present teachings. As still another example, while the R-TONES-REQ signal has been shown as a preferred signal communicated by the data pump and a C-TONES has been shown as a preferred response received by the data pump, other signals may be used. As yet another example, while modem  50  has been shown to include both DSL and voice functionality, in an alternative embodiment only the DSL functionality need be supported. As still another example, while an incrementing COUNT is implemented above to limit the number of DSL connection attempts in method  70 , a timeout feature could be used as an alternative. As still another example, while an RJ 11  connector using only four pins has been described as the connector to which modem  50  is connected, an RJ 11  connector using six pins also may implement the inventive teachings, where by way of example those six pins may be categorized as three different pairs of pins, and the method described earlier may be expanded and applied to this configuration whereby each of the three different pairs of pins are alternately selected via a switch and a determination is then made for each pin pair as to whether a response is received (or whether a POTS signal exists or whether a measured impedance provides a basis for evaluating connectivity). Indeed, as yet a final example, still other connectors providing a DSL service and/or with a different pin configuration also may benefit from the above-described teachings. Thus, these as well as other examples ascertainable by one skilled in the art further exemplify the inventive scope, as is defined by the following claims.