Patent Publication Number: US-2005117734-A1

Title: System and method for telephone number portability

Description:
RELATED APPLICATIONS  
      The present invention claims priority on provisional patent application Ser. No. 60/517,812, filed on Nov. 6, 2003, entitled “Device and Methodology for Simplifying the Local Number Portability Process by Allowing Multiple Carriers Simultaneous Access to customer Wiring”. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates generally to the field of telephony and more particularly to a system and method for telephone number portability.  
     BACKGROUND OF THE INVENTION  
      Telephone numbers are an integral part of a consumers&#39; identity in the community and the ability to allow a customer to retain their phone number provides the basis for true local telephone competition. Providers of alternative telephone services need to be able to port (or reuse) the customer&#39;s existing telephone number to be competitive. Alternate provides as used herein are defined as those providers not dependent on the Local Exchange Carriers (LEC) to access a customer&#39;s premise. Alternative providers may access the customer&#39;s premise by non-LEC twisted pair wire, coaxial cable, optical fiber, or wireless. The responsibility for porting an existing telephone number resides with the current provider which is usually the incumbent local exchange carrier.  
      Because the incumbent local exchange carrier (ILEC) is a direct competitor of the alternative provider, the local number porting (LPN) process is frequently contentious, cumbersome, and time consuming. The process requires a coordinated process between the incumbent local exchange carrier and the alternative provider with associated cost for both. The incumbent local exchange carrier must “port out” the telephone number (remove the telephone number from its customer service base) at the same time as the alternative provider “ports in” the telephone number (adds the telephone number to its customer base) in order for the customer to have continuous service.  
      Typically the incumbent local exchange carrier and the alternative provider agree on a date and time for the “porting” of the telephone number to take place. At the appointed time the alternative provider service technician and the incumbent local exchange carrier service technician perform what is referred to as a “hot cut”. The incumbent local exchange carrier service technician causes the appropriate databases within the public switched telephone network (PSTN) to be updated with the new information identifying the alternative provider as the service provider or “owner” of the telephone number. The alternative provider&#39;s service technician simultaneously updates the appropriate databases within the alternative provider&#39;s systems to “provision” the subscriber so that the alternative provider is now the service provider. Inbound and outbound calls will now pass through the alternative provider&#39;s equipment.  
      Because of the amount of required coordination and labor involved there is a high probability that errors will occur during the telephone number “porting”. This results in additional costs and frustration on the part of the customer.  
      Thus there exists a need for a system and method of telephone number porting that increases the probability of success of telephone number porting.  
     SUMMARY OF INVENTION  
      A system for telephone number portability that overcomes these and other problems has a first switch coupled between a first external telephone line and a users telephone. A second switch is coupled between a second external telephone line and the users telephone. A controller selectively opens and closes the first switch based on an incoming telephone call. The first external telephone line may be a local exchange carrier telephone line. The controller may close the first switch and open the second switch when there is the incoming telephone call. The second external telephone line may not be a local exchange carrier telephone line. The controller may open the first switch and close the second switch when there is not the incoming telephone call. The controller may open the first switch and close the second switch when there is an out going telephone call. The first external telephone line may be a number of telephone lines.  
      In one embodiment a system for telephone number portability has a switch network that couples at least two external telephone lines to a users telephone. A controller changes a state of the switch network based on an incoming telephone call. One of the at least two external telephone lines is an incumbent local exchange telephone line. One of the at least two external telephone lines is an alternative provider telephone line. The switching network opens a switch to the incumbent local exchange telephone line when there is not the incoming telephone call. The switching network opens a switch to the alternative provider telephone line when there is the incoming telephone call. The switching network closes a switch to the incumbent local exchange telephone line when there is the incoming telephone call. The switching network closes a switch to the alternative provider telephone line when there is not the incoming telephone call. The user&#39;s telephone may be any appliance attached to a telephone line. The appliance may be a facsimile machine. One of external telephone lines may be carried over a coaxial cable. One of the external telephone lines may be an electromagnetic signal carried over the airwaves.  
      In one embodiment a method for telephone number portability includes the steps of determining if there is an incoming telephone call. When there is the incoming telephone call, a switch is closed between a users telephone and an external incumbent local exchange telephone line. When there is the incoming telephone call, a switch opened between an external alternative providers telephone line and the users telephone.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic diagram of a system for telephone number portability in accordance with one embodiment of the invention;  
       FIG. 2  is a block diagram of a system for telephone number portability in accordance with one embodiment of the invention; and  
       FIG. 3  is a block diagram of a system for telephone number portability in accordance with one embodiment of the invention.  
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
      The present invention is a system and method for telephone number portability. The system has a controller(s) and switches that selectively connect a user&#39;s telephone to either an incumbent local exchange carrier or the alternative provider based on an incoming telephone call.  
       FIG. 1  is a schematic diagram of a system  10  for telephone number portability in accordance with one embodiment of the invention. A customer premise  12  has a number of telephones  14  coupled to inside wiring  16 . The customer premise may be either a residence or a business. The inside wiring  16  is coupled to an existing incumbent local exchange carrier&#39;s network interface unit  18 . The inside wiring  16  is coupled to the switching device  20 . The switching device  20  is coupled to a network interface unit (NIU)  18 . This is the incumbent local exchange carriers access point. The network interface unit  18  is coupled to the incumbent local exchange carriers external telephone line  22 .  
      The inside wiring  16  is also coupled to a second switching device  24 . The second switching device  24  is coupled to an alternative providers interface unit  26 . This is the alternative provider&#39;s access point. The alternative interface unit  26  is coupled to an alternative provider&#39;s external telephone line  28 .  
      In operation the switching devices are installed when a customer requests service from an alternative provider and wants to keep his telephone number. The first switching device  20  is designed so that a switch between the incumbent local exchange carrier&#39;s external telephone line  22  and the user&#39;s telephones  14  is open unless an incoming call over telephone line  22  is detected. The second switching device  24  is designed so that a switch in the device  24  is closed except when there is an incoming call on telephone line  22 . There are four possible situations for the switching devices. In the default state the alternative provider telephone line  28  is connected to the user&#39;s telephones  14  and the incumbent local exchange carrier&#39;s external telephone line  22  is disconnected from the user&#39;s telephones  14 . A second situation is when there is an off hook, an outbound call and then an on hook. When the telephone  14  goes off hook, the inside wiring  16  changes from twenty eight volts direct current (±28 VDC) to seven volts direct current (±7 VDC). The dialed digits (dual tone multi-frequency DTMF) are passed to the alternative provider telephone  28 . When the call has ended, the telephone call goes back on-hook and the inside wiring  16  returns to twenty eight volts direct current (±28 VDC). The switching devices  20 ,  24  stay in there default state during this situation. Another situation is an inbound call over the ILEC telephone line  22  and no off hook event, in other words no answer to a ring. The switching device  20  detects a ring voltage (90 VAC @ 20 Hz). The switching device  20  connects the ILEC telephone line  22  to the inside wiring  16 . The second switching device  24  detects the ring voltage and disconnects the alternative provider telephone line  28 . When a ring voltage is not detected by the switching devices  20 ,  24  after one ring interval in one embodiment, the switching devices  20 ,  24  revert to their default state where the ILEC line  22  is disconnected and the alternate provider telephone line  28  is connected. Another situation is an inbound call over the ILEC telephone line  22  and off hook event (the call is answered) and an on hook event (user hangs up). The switching device  20  detects a ring voltage (90 VAC @ 20 Hz). The switching device  20  connects the ILEC telephone line  22  to the inside wiring  16 . The second switching device  24  detects the ring voltage and disconnects the alternative provider telephone line  28 . The telephone  14  goes off hook and the inside wiring  16  drops to seven volts direct current (±7 VDC). When the telephone  24  goes back on hook (user hangs up) the inside wiring transitions to twenty eight volts direct current (±28 VDC). The first switching device  20  detects this transition and disconnects the ILEC telephone line  22 . The second switching device  24  detects this transition and connects the alternative provider line  28 . The examples above are illustrative but not limiting. For instance, the voltages cited could be different.  
       FIG. 2  is a block diagram of a system  40  for telephone number portability in accordance with one embodiment of the invention. A telephone  42  is connected by internal wiring  42  to a first switch  44  and to a second switch  46 . The first switch  44  and the second switch  46  are connected to a controller  48 . Note that each switch may have its own controller or a single controller may control both switches. In addition, the controller may be a microcontroller that runs embedded software or it may be constructed of electronic logic elements. The first switch  44  is connected to an ILEC telephone line  50  and the second switch  46  is coupled to an alternative provider telephone line  52 . The device(s) incorporating the switches  44 ,  46  and controller  48  are installed when a customer requests that their local carrier be changed and that they keep their telephone number. From the time that the local number porting (LNP) process is requested until it is completed, the first switch  44  is in a normally open state. This example assumes that the customer is changing from the ILEC to the alternative provider, but the system will work equally well if the situation is reversed. The second switch  46  is normally closed. When a ring signal is present on the ILEC telephone line  50 , the controller  48  detects this and closes the first switch  44  and opens the second switch  46 . This allows the telephone  42  to receive calls from the ILEC until the telephone number is ported to the AP. When a ring signal is not detected for a predetermined period of time and no off hook signal is detected, the controller  48  opens the first switch  44  and closes the second switch  46 . When an off hook signal is detected (after a rings signal from the ILEC line  50 ) and then a subsequent on hook signal is detected, the controller  48  opens the first switch  44  and closes the second switch  46 . Note that once the telephone number is ported to the alternative provider the system always remains in the default state and is transparent to the user. Alternatively the system may be designed so that both switches are normally open until an inbound call is sensed on either line and then the switch associated with that line is closed. In this case, an off hook switch without a ring signal (out bound call) results in the controller  48  closing the second switch  46  and leaving the first switch  44  open. Note that having the ILEC telephone line  50  normally disconnected significantly reduces the load that would be imposed by the telephone line  50  otherwise.  
       FIG. 3  is a block diagram of a system  70  for telephone number portability in accordance with one embodiment of the invention. A user&#39;s telephone  72  is coupled to a switching network  74 . The state of the switching network  74  is controlled by a controller  76 . The switching network  74  is coupled to a number of external phone lines. One of the external telephone lines  78  is a twisted pair telephone line owned by an incumbent local exchange (ILEC) carrier and connected to the ILEC network  80 . An alternative provider network  82  may be connected by a satellite  84  or tower  86  wirelessly to the switching network  74  or by a cable television  88  cable  90  or a fiber optic cable. The switching network  74  allows a number of telephone lines to be ported at one location from a first service provider to a second provider. If a user wants to switch one or more telephone numbers from the ILEC  80  to an AP  82 , the switching network would normally connect the phone(s)  72  to the AP line  90  and disconnect the ILEC line  78 . When an inbound call from the ILEC line  78  is detected by the controller  76 , the switching network  74  couples the telephone line  72  to the ILEC line  78  and disconnects the AP line  90 . When the telephone call is ended or not picked up, the switching network  74  disconnects the telephone  72  from the ILEC line  78  and couples the telephone  72  to the AP line.  
      Thus there has been described a system and method of facilitating local number porting that does not require coordination between the ILEC and AP service technician. This is because a “hot cut” is no longer necessary to provide the customer with continuous service. The system is inexpensive enough that it may be left in place even after the local number has been ported.  
      While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alterations, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alterations, modifications, and variations in the appended claims.