Abstract:
Apparatus for linking multiple baseband telephone lines to provide broadband communication. The apparatus comprises a broadband port, a plurality of baseband ports, and a controller. The broadband port provides connection to a broadband device or broadband communication line. The baseband ports provide connection to baseband communication lines. The controller integrates baseband data streams accepted at the baseband ports into a broadband data stream for transmission at the broadband port, and/or demultiplexes a broadband data stream received at the broadband port into baseband streams for transmission at the baseband ports. The baseband data include message data corresponding to the message data of the broadband stream, and control data describing an interrelationship among the message data, for controlling integrating of said baseband message data. The invention allows an individual to use multiple plain old telephone service (POTS) lines in combination to emulate the capability of a broadband line.

Description:
TECHNICAL FIELD  
         [0001]    The invention relates to a method and apparatus for connecting high data rate telephone calls over conventional low data rate telephone lines.  
         BACKGROUND OF THE INVENTION  
         [0002]    Communication network subscribers have the option of subscribing to plain old telephone service (POTS) or high data rate service, e.g. ISDN (integrated services digital network). POTS is suitable for voice communication, low data rate data communications, and computer transmission via modem and facsimile. ISDN service is suitable for high data rate data communications, e.g. high data rate computer transmissions and video.  
           [0003]    To have access to the greater data rate of ISDN service, a subscriber must make arrangements before he needs the high data rate to have the ISDN service connected. In many situations, however, the individual does not have the option to have ISDN service connected, e.g. when calling from a public area. ISDN service has the additional disadvantages that the subscriber (a) has to pay to have the ISDN line installed and (b) has to pay a monthly fee for the ISDN connection in excess of that for a POTS connection.  
         SUMMARY OF THE INVENTION  
         [0004]    The invention provides method and apparatus by which a telephone subscriber can obtain the benefits of high data rate communication using low data rate (baseband) POTS telephone lines. Individuals using the invention will be able to take advantage of higher data rate communication on demand, from any location with multiple POTS lines installed, and without being charged for connection to ISDN service.  
           [0005]    In general, in one aspect, the invention features a broadband port for connection to a broadband device or broadband communication line; baseband ports for connection to baseband communication lines; a controller for integrating baseband data streams accepted at said baseband ports into a broadband data stream for transmission at said broadband port, said accepted baseband data including message data for conveyance at said broadband port and control data describing an interrelationship among the message data received on said baseband ports, and for demultiplexing a broadband data stream received at the broadband port into a plurality of baseband data streams for transmission at the baseband ports.  
           [0006]    The advantages of the invention include the following. A broadband call can be placed to or from a location where no broadband line is available. For instance, in an airport, a user could use two or four adjoining pay stations to connect a broadband call. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIGS. 1 and 2 are block diagrams of a telephone network, including apparatus in accordance with the invention.  
         [0008]    [0008]FIG. 3 is a block diagram of a node in accordance with the invention.  
         [0009]    [0009]FIG. 4 is a flowchart showing setting up a node and adapter within a network.  
         [0010]    [0010]FIGS. 5 and 6 are flowcharts showing connection of ISDN calls over POTS lines. 
     
    
     DESCRIPTION  
       [0011]    Referring to FIGS.  1 - 2 , the invention allows a telephone user to tie together several POTS lines, and thereby achieve high data rate communications over low data rate POTS lines. In the embodiment of FIGS.  1 - 2 , the high data rate data ordinarily carried over an ISDN line  102  of a telephone network  100  are parceled out over four POTS lines  104 ,  108 ,  112 ; a fifth POTS line  106 ,  110 ,  114  is used to coordinate the data of the other four  104 ,  108 ,  112 . This tying together is accomplished by two cooperating devices: an adapter  118  at the user&#39;s location, and a node  300  that is part of network  100 . The user&#39;s ISDN terminal  120  connects to one side of the adapter; the five POTS lines  104 ,  106  connect to the other. The five POTS lines  104 ,  106  connect through POTS lines  108 ,  110 ,  112 ,  114  to node  300 .  
         [0012]    Node  300  interfaces POTS lines  112 ,  114  to ISDN line  102 . For data bound from local terminal  120  to remote device  122  (right-to-left in FIGS. 1 and 2), node  300  uses the coordination data of fifth POTS line  114  to reassemble data on the other four lines  112  into a single ISDN stream; this stream is delivered to a remote ISDN device  122  in the conventional fashion over ISDN line  102 . Similarly, data from the remote device  122  travel on a conventional ISDN line (left-to-right FIGS. 1 and 2) to reach node  300 . Node  300  apportions these high-rate data among the four POTS lines  112 , and transmits coordination data on the fifth POTS line  114 . When these data reach adapter  118 , adapter  118  uses coordination data of fifth POTS line  106  to reassemble the original data stream. Adapter  118  presents the reassembled data to ISDN terminal  120  as if they had arrived on a conventional ISDN line.  
         [0013]    A conventional network  100  includes POTS lines  104 - 114  and ISDN PRI (primary rate interface) lines  102  that are routed through a number of switches  130 ,  132 ,  134  from a local terminal  120  to a remote device  122 . The lines included in this connection will typically be owned by several different carriers, e.g., a local exchange carrier (LEC)  140  and an inter-exchange carrier (IXC)  142 . The network lines will include an ISDN PRI line  102  and POTS lines  104 - 114 .  
         [0014]    Conventionally, a voice/video device  122  that requires ISDN communication is connected to an ISDN line  102  of network  100 . Such ISDN devices can include computer or video terminals or any other type of system that requires a ISDN connection.  
         [0015]    A user who wishes to use a ISDN device, e.g., a voice/video terminal  120 , but who has no ISDN line  102  reaching his location, uses adapter  118  to connect his voice/video terminal  120  to the POTS lines  104 ,  106  of network  100 . Terminal  120  is connected to adapter  118 , typically using voice, data, and video lines  150 , or a line having transmission characteristics essentially similar to those of an ISDN line  102 . Adapter  118  acts as a multiplexer/demultiplexer: when terminal  120  generates data for transmission over network  100 , adapter  118  disassembles the ISDN data stream received on lines  150  into four data streams, and transmits these four low data rate streams over POTS lines  104 . An additional data stream, that includes data to control the reassembly of the four data streams into a single ISDN data stream, is generated by adapter  118  and transmitted over a fifth POTS line  106 .  
         [0016]    In the embodiment of FIG. 2, the message data of the original ISDN line  102 ,  150  are carried on four POTS lines  104 ,  108 ,  112  with a fifth POTS line  106 ,  110 ,  114  carrying coordination data. The number of POTS lines  104 ,  108 ,  112  used in any particular embodiment will vary with the data rates required by the communication between terminal  120  and device  122  and the data rate capacity of the individual POTS lines. Because an ISDN line has a capacity of 112,000 bits/sec, many devices use this as the maximum data rate at which they will transmit. Four POTS lines, at 28,800 bits/sec. each, are sufficient, collectively, to meet the 112,000 bits/sec. capacity requirement. Devices that have higher data rates would require more POTS lines, and devices that have lower data rates could use fewer. Similarly, as POTS modem rates improve, fewer lines will be required to provide the data rate of a single ISDN line.  
         [0017]    Travelling over the POTS lines  104 - 114  of the network  100 , these five POTS lines reach node  300 , located in network  100 . The geographical location of node  300  is immaterial; the switches  130 - 134  will arrange a continuous circuit from adapter  118  to node  300  as part of connecting the call.  
         [0018]    To support adapter  118 , the telephone network incorporates node  300 . Node  300  has the capability to reassemble the four data streams on POTS lines  112 , using control and coordination information from POTS line  114 , into a single ISDN data stream for transmission over ISDN line  102 .  
         [0019]    In another embodiment, the message data and coordination data are distributed evenly over voice lines  104 - 114 . For instance, a 56 Kbits/sec data stream can be carried over three voice lines, each carrying 28,800 bits/sec. In this configuration, each of the three lines carry a third of the message data and a third of the coordination data. The data would be grouped in packets, and each third packet would be sent over each of the three lines: line  1  might carry packets  0 ,  3 ,  6 ,  9 ,  12 , . . . , line  2  might carry packets  1 ,  4 ,  7 ,  10 ,  13 , . . . and line  3  might carry packets  2 ,  5 ,  8 ,  11 ,  14 , . . . The framing header of each packet would bear a synchronization stamp, for instance, a 16-bit field incremented from 0 to 65,535, circularly. At the receiving end, the packets are buffered, until they can be processed in synchronization stamp order.  
         [0020]    ISDN PRI line  102  connects node  300  to a remote voice or video device  122 . Line  102  is routed from node  300  to remote device  122  through several switches  134 . Typically ISDN line  102  will include segments owned by two or more different carriers, just as lines  104 - 114  were owned by the LEC  140  and IXC  142 . Device  122  receives the data on line  102  and displays them as video, or presents them as sound, as agreed by the local terminal  120  and remote device  122 .  
         [0021]    Data produced by remote device  122  will be transmitted to the network over ISDN line  102  to node  300 . Node  300  will disassemble data  102  into four low data rate data streams  112 , plus a fifth stream of coordination data  114 . POTS lines  104 - 114  will convey these data back to adapter  118 . Adapter  118  will use coordination data received on fifth POTS line  106  to reassemble the four low-data rate streams  104  into a single ISDN stream  150 . This ISDN stream will then be conveyed to the local terminal  120 , for appropriate display or presentation.  
         [0022]    [0022]FIG. 3 shows a more detailed block diagram of node  300 . Node  300  has an ISDN port  302  for connection to ISDN line  102 . For each POTS line  112 ,  114  to be connected to node  300 , node  300  has a modem and POTS port  306 . The modems and ports together form a modem bank  304 . In some embodiments, node  300  might have one ISDN port  302  and five POTS modem ports  306 . In other embodiments, node  300  might have several ISDN ports  302 , and roughly five times as many POTS modem ports  306 , so that node  300  can route several calls between several pairs of terminals  120  and devices  122  simultaneously.  
         [0023]    For conveying data from/to modem bank to/from ISDN port  302 , node  300  has a data processor  310 . Data processor  310  includes a CPU  312  and a memory  314 . Memory  314  includes a database memory  318  and storage for the program code executed by CPU  312 . Database  318  stores information about the connections and interrelationships between the POTS lines  112 ,  114  and the ISDN lines  102 . For example, database  318  might store information recording that POTS ports one through five are connected to ISDN line number three and store the phone numbers of the lines to which POTS ports one through five are connected to. CPU  312  executes software that reads the coordination data received on POTS line  114  and uses them to reassemble the message data received on POTS lines  112  for transmission on ISDN line  102 . CPU  312  also executes software that disassembles data received at ISDN port  302  and transmits them at the appropriate POTS ports  306 . Each POTS port  306  has a buffer to store received message data temporarily, until the reassembly information is received over the fifth POTS line. Similarly, the buffers hold outgoing message data until the coordination of the streams is completed. The multiplexing and demultiplexing functions are performed by CPU  312  according to methods used by multiplexers and demultiplexers in conventional telephone circuit switches.  
         [0024]    At the level of detail of the block diagram of FIG. 3, adapter  118  is essentially similar to the node  300  shown in FIG. 3, except that adapter  118  has only one set of POTS lines and one ISDN line, rather then the n sets of POTS lines and n ISDN lines shown in FIG. 3. Indeed, both adapter  118  and node  300  could be two “boxes” of the same model (of course one, adapter  118 , would be physically located at the local user&#39;s location, and the other, node  300 , would be geographically located at the convenience of the carrier) though the programming of the two CPU&#39;s might differ slightly.  
         [0025]    [0025]FIG. 4 illustrates a setup phase, where a user informs the telephone service provider of the existence of adapter  118 , and its configuration relative to network  100 . FIG. 5 illustrates the steps of connecting a ISDN call over network  100 , using the information provided during the setup phase of FIG. 4. FIG. 6 illustrates connecting a call from terminal  120  to device  122 .  
         [0026]    Referring primarily to FIG. 4 and secondarily to FIGS. 1, 2 and  3 , to connect adapter  118  to network  100 , in step  410 , the user determines the number of telephone lines needed to convey an ISDN call. This determination will consider the baud rate of the ISDN line that is to be emulated and the baud rate of the individual POTS lines. With this number in hand, the user ensures that a sufficient number of POTS lines are installed. In the remaining steps of the method, either the phone numbers of node  300  and lines  112 - 114  are determined and stored in a memory of adapter  118 , or else the phone numbers of lines  104 - 106  of adapter  118  are determined and stored in a memory of node  300 . It may be advantageous to do both.  
         [0027]    In step  412 , the user determines the telephone numbers of the telephone lines he intends to use to send or receive a ISDN call. In step  414 , the local user connects the POTS lines  104 ,  106  to adapter  118 . In some embodiments, the user notes the correspondence between the phone numbers of the lines and the ports of the adapter to which the lines are connected, so that node  300  and adapter  118  can agree which signals are to be transmitted on which lines.  
         [0028]    In step  416 , the local user notifies the communication service provider  142  of the number of telephone lines  104  connected to adapter  118  and the telephone numbers of those telephone lines. In the embodiments discussed above, the user also notifies the provider of the correspondence between the telephone numbers and the adapter ports to which the lines are connected. The user can so notify the communication service provider  142  through any suitable means, e.g. a telephone call. In step  418 , the communication service provider  142  stores into database  520  the number of the telephone lines  104 ,  106  connected to adapter  118 , the telephone numbers of the telephone lines  104 ,  106  and the order the telephone lines were connected to adapter  118 . In step  420 , the call between local terminal  120  and the communication service provider is disconnected. Adapter  118  is now prepared to receive an inbound ISDN call over the telephone lines  104 ,  106  (step  422 ).  
         [0029]    In some embodiments, steps  412 - 418  are automated. The user need not take special care to record the correspondence between the phone numbers and the ports of adapter  118 . In these embodiments, the adapter has a processor and memory. As a multi-POTS-line ISDN call is being connected, the node&#39;s CPU  312  will communicate with the processor at adapter  118 . This communication will establish the correspondence between node ports  306  and the respective ports of adapter  118 . In one family of such embodiments, steps  414 ,  416 , and  418  might proceed as follows. The user stores all of the phone numbers of the adapter POTS ports into the memory of adapter  118 , and gives a “setup network” command to adapter  118 . Adapter  118  then calls the network using one of its POTS lines  106 , e.g., reaching CPU  312  of node  300 . Over this call, adapter  118  tells node  300  the number of POTS lines connected, and the phone numbers of lines  104 ,  106 . This information is stored in database  520 .  
         [0030]    Alternatively, the local user can simply plug a sufficient number of phone lines into adapter  118 . When the user directs adapter  118  to perform the initialization process of FIG. 4, adapter  118  tests its modem ports to determine how many lines  104 - 106  are connected. Adapter  118  calls to node  300  on a single line, typically calling a hunt group phone number of node  300 , programmed into adapter  118 . Adapter  118  tells node  300  the number n of lines  104 - 106  that are connected. Node  300  responds by reserving n- 1  ports  306 , and communicating to adapter  118  the n- 1  phone numbers of the reserved lines  112 ,  114  over which to connect.  
         [0031]    Alternatively, the local user can simply plug a sufficient number of phone lines into adapter  118 . During the initialization process of FIG. 4, adapter  118  tests its modem ports to determine how many lines are connected. Adapter  118  will then call telephone node  300  over each of the connected lines, and allow a caller ID feature to identify the phone number on which the adapter is calling to CPU  312  of node  300 . Node  300  can then hang up and call back to adapter  118  on these identified lines. Adapter  118  and node  300  will exchange information to associated the lines of the broadband call with each other, and to distinguish these calls from the calls of other calls to node  300  from other adapters  118 .  
         [0032]    Alternatively, when the first call is connected, node  300  can provide to adapter  118  over this first call n- 1  telephone numbers of n- 1  baseband ports  306  of node  300 , to which adapter  118  can call to connect the n- 1  additional baseband phone calls.  
         [0033]    Alternatively, the n telephone numbers of n baseband ports  306  can be stored in a non-volatile memory of adapter  118 .  
         [0034]    Alternatively, each adapter  118  can have a node phone number reserved to it, and all lines of adapter  118  can be phoned to node  300  on that single phone number (with call roll-over) so that the individual voice lines  104 - 114  of a single broad band call are associated with each other.  
         [0035]    Alternatively, each adapter  118  can have a unique device ID, for instance encoded in a non-volatile ROM. When the adapter  118  calls in on the n lines, the device ID can be exchanged over the n lines so that node  300  can associate the associate the calls from a single node  118 .  
         [0036]    Alternatively, when the first call is connected, node  300  can generate a unique call tag value, and communicate this to adapter  118 . As adapter  118  connects the n- 1  remaining calls to ports  306 , adapter  118  provides this call tag value to node  300 , which in turn uses the call tag value to associate the n separate baseband calls into a single group.  
         [0037]    [0037]FIG. 5 illustrates connecting a call, in the case where a call originates at remote device  122  (at the left end of FIGS. 1 and 2) to local terminal  120  (at the right end). Referring primarily to FIG. 5 and secondarily to FIGS. 1, 2 and  3 , in step  502 , the remote device makes a ISDN call over ISDN lines  102  using the procedures conventionally used to connect to any other ISDN device. Usually this ISDN call will be made over a translatable telephone number, e.g. an 800 service telephone number, such that reference to a database will be required to connect the call.  
         [0038]    In step  504 , network switch  132  intercepts the call, recognizing the destination phone number as one that must be connected over multiple POTS lines rather than over an end-to-end ISDN line. Switch  132  has a database  520 , analogous to the database that translates “800” numbers into a true area code and phone number. In steps  506 - 510 , switch  132  uses this database to connect three call segments. A first segment, ISDN line  522 , connects switch  132  and node  300 . A second segment, over POTS lines  112 ,  114 , connects node  300  and switch  132 . A third segment, POTS lines  104 - 110 , connects switch  132  to adapter  118 . Steps  506 - 510  may be reordered relative to each other, or may be overlapped in time.  
         [0039]    In step  506 , switch  132  consults database  520  to translate the ISDN phone number dialed by remote device  122  into the telephone number of at least one of the POTS lines  104 ,  106  connected to adapter  118  at the local user&#39;s location. In one embodiment, database  520  stores the number of POTS lines  104 ,  106  connected to adapter  118 , the phone number of each of these lines, and the association between each line and the corresponding port of adapter  118 .  
         [0040]    In step  508 , switch  132  connects the appropriate calls over lines  104 - 114  in accordance with the information obtained in step  506  from database  520 . As the lines  104 - 110  are connected, node  300  and adapter  118  will test the lines to determine their quality and capacity. For instance, some voice lines will carry a full 28.8 Kbits/sec; as discussed above, it is believed that three of these lines will readily carry the message data and coordination data for a 56 K bit/sec transmission. However, if the lines are somewhat noisy or ill-conditioned, then the set up phase of FIG. 4 may determine that a line can only carry less than 28.8 Kbits/sec, and that more than three lines are needed.  
         [0041]    In step  510 , switch  132  connects POTS segments  112  and  114  and ISDN segment  522 . The number of POTS lines in segment  112  will agree with the number of POTS lines  104  determined by consultation of database  520 . In making these connections, the connection of respective lines of segments  112 ,  114  to lines  104 - 110  will be made to preserve the proper association between modem ports  306  (FIG. 3) of node  300  to the POTS ports of adapter  118 . For example, the coordination data line  114  of node  300  will be connected to coordination data line  106  of adapter  118 , not to message data line  104 .  
         [0042]    In step  512 , a high data rate call is connected between terminal  120  and device  122 . Part of the call is carried over ISDN lines  102 ,  522 , from device  122  to node  300 , and part over POTS lines  104 - 114  from node  300  to adapter  118 . Control software, primarily in switch  132 , has consulted database  520  to ensure that the POTS lines  104 - 110  are sufficient in number to carry the data rate of ISDN line  102 , and that POTS lines  104 - 114  connect ports of node  300  to corresponding ports of adapter  118 .  
         [0043]    In the embodiment described, steps  506 ,  508 , and  510  are performed by switch  132 . Alternatively, much of the handshaking to establish the multiple POTS connections can be performed by node  300 . Similarly, database  520  of information required to connect the multiple POTS calls may reside at, or be distributed among, any of several locations. For example, FIG. 1 shows database  520  connected to switch  132 . In a first alternative, much of the information of database  520  could reside in a database connected to node  300 , e.g. database  318  of node  300  (FIG. 3).  
         [0044]    In a second alternative embodiment, database  520  could store only a single one of the phone numbers of local ISDN terminal  120 , and much of the remaining information could be stored in a database residing in adapter  118 . In this alternative, for example, switch  132  would initially connect to adapter  118  over a single POTS line  106 ,  110  and switch  132 ; then adapter  118  and switch  132  would handshake to exchange information over this initial call, to establish the additional calls required to complete the high data rate call over multiple POTS lines. This handshaking could include, for example, adapter  118  providing to switch  132  the phone numbers of the remaining POTS ports  104  of adapter  118 . Switch  132  would then connect the additional POTS calls over the phone numbers provided during the initial handshaking.  
         [0045]    Steps  508  and  510  establish the n calls between node  300  and adapter  118 , and establish a correspondence of the calls to each other. Many alternative embodiments of these steps exist, for instance those corresponding to the alternative embodiments of steps  416 - 418  discussed above. These alternatives will be readily understood by one of ordinary skill, without elaboration here.  
         [0046]    Referring primarily to FIG. 6 and secondarily to FIGS. 1, 2, and  3 , a high data rate call from the local terminal  120  to the remote device  122  is completed in accord with method  600 , using the setup information established by the method of FIG. 4. In step  610 , the local user issues a command to adapter  118  to connect a call to the desired ISDN phone number of remote device  122 . In step  612 , adapter  118  connects a single POTS call to node  300 .  
         [0047]    In step  614 , processor  312  in node  300 , and processors in switch  132  and adapter  118  handshake over this single line. The processors consult database  318  in node  300 , database  520  in switch  132 , and a database (if any) in the memory of node  118 . This handshaking establishes the number of POTS calls  104 - 114  required to carry the data rate of the ISDN line  102 , the phone numbers which must be dialed, whether node  300  is to dial adapter  118  or vice-versa, and the correspondence between the phone numbers and ports of node  300  and adapter  118 . One correspondence might be to note the order in which the lines are connected to the ports of adapter  118 . For example, node  300  might provide to adapter  118  four additional phone numbers for adapter  118  to call, over which to establish the message lines  104 ,  106 ,  112 . Another would be to establish this correspondence by handshaking information between node  300  and adapter  118 . Another would be to associate the lines in the order that the calls are connected.  
         [0048]    Typically, the additional POTS calls will be placed by adapter  118  to node  300  so that tolls will be billed correctly, although it is also possible that the additional POTS calls will be connected by node  300  to adapter  118 . In the adapter-calls-node configuration, it is preferred that node  300  reserve the appropriate number of inbound POTS ports  306 , so that these lines will be available as adapter  118  calls to connect the individual lines.  
         [0049]    In step  616  (which may proceed in parallel with step  614 ), the ISDN link  102  between node  300  and remote device  122  is established.  
         [0050]    In step  618 , the ISDN call is connected between terminal  120  and device  122 . ISDN message communication may now begin.  
         [0051]    It is to be understood that the above description is only of one preferred embodiment of the invention. Numerous other arrangements may be derived by one skilled in the art, without departing from the scope of the invention. The invention is thus limited only as defined in the accompanying claims.