# US 5,583,926 A · Method and apparatus for routing a call to a number corresponding to a virtual public dial plan or to an existing dial plan

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- Number: US 5,583,926 A
- Document ID: US5583926A
- Status: Granted
- Kind: A
- Application number: 08/366,650
- Filed: 1994-12-30
- Granted: 1996-12-10
- Earliest claimed: 1994-12-30
- Assignees: Stentor Resource Centre, Inc.
- Inventors: Daniel J. Venier; L. Lloyd Williams; R. William Carkner; Morlen R. Reynolds
- Web page: https://patentgrep.com/patent/US5583926A

## CPC

- H04M 3/4228: {in networks}
- H04Q 3/0016: {Arrangements providing connection between exchanges}
- H04Q 3/0029: {Provisions for intelligent networking}
- H04Q 2213/13531: virtual networks - inc. PVN
- H04Q 2213/13542: numbering plans, e.g. number re-allocation
- H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08)
- H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W)

## Abstract

A method for creating a virtual public numbering domain, which will coexist with and be parallel and non-intrusive to the existing geographic North American telephone network numbering plan is disclosed. It will have sufficient capacity to provide additional and more flexible numbering resources which will stimulate and enable many new service applications. The existing telephone network infrastructure has digital switching points and a database system. The method consists of receiving at one of the digital switching points a called number, and verifying whether the number called is a number of the virtual public dial plan. If the number called is a number of the virtual public dial plan, the next steps consist of forming with the number called a virtual public address of predetermined length, supplying the virtual public address to the database system to determine a corresponding network node address, supplying the corresponding network node address to the digital switching point and routing the call through the network infrastructure according to the existing dial plan. If the number called is a number of the existing dial plan, the call is routed through the network infrastructure according to the existing dial plan and the number called.

## Claims

### Claim 1

In a telephone network having a number of telephone switching offices equipped with SSPs (Service Switching Points) operating with AIN (Advanced Intelligent Network) application software, and a remotely located SCP (Service Control Point) adapted to receive, when required, SS7 (Signalling System 7) messages from the SSPs to translate a dialed number to enable the routing of a call on the telephone network, a method of providing a parallel, non-intrusive virtual public dial plan (VPDP), co-existing with the current network North American numbering plan (NANP), to enable a calling party to dial a virtual, public telephone number without the dialing limitations of the NANP, comprising the steps of:
a) providing a VPDP access code which, when dialed as a prefix to the virtual, public telephone number, enables a calling party, to reach a destination station via the VPDP;
b) setting up an AIN trigger at AIN capable SSPs, said AIN trigger being responsive to said VPDP access code;
c) launching a query from said AIN capable SSPs to said remotely located SCP when said AIN trigger detects a VPDP access code; and
d) providing a VPDP to NANP translation table at the SCP, such that when the virtual, public telephone number dialed by the calling party is received at the SCP, the dialed number can be translated to a NANP telephone number for routing to the destination station.

### Claim 2 (depends on 1)

A method as defined in claim 1, wherein the step of launching a query from said AIN capable SSPs further comprises the steps of:
i) forming, at said SSP, an SS7 message comprising the dialed virtual, public telephone number;
ii) sending the SS7 message from said SSP to said SCP along a common signaling channel;
iii) receiving the SS7 message at said SCP;
iv) translating the virtual, public telephone number in the SS7 message to a routing number corresponding to a telephone number associated with the NANP; and
v) sending a response SS7 message from said SCP to said SSP, said SS7 message containing said routing number, such that the call can be routed to said destination station.

### Claim 3 (depends on 2)

A method as defined in claim 2, wherein the AIN trigger is a Public Office Dial Plan trigger.

### Claim 4 (depends on 2)

A method as defined in claim 2, wherein the AIN trigger is a customized dial plan trigger.

### Claim 5 (depends on 2)

A method as defined in claim 2, wherein the VPDP access code is deleted prior to forming the SS7 message.

### Claim 6 (depends on 5)

A method as defined in claim 5, wherein the VPDP access code is a character not used in the NANP.

### Claim 7 (depends on 6)

A method as defined in claim 6, wherein the VPDP access code is the number (#) sign.

### Claim 8 (depends on 2)

A method as defined in claim 2, wherein calls having a VPDP access code, and which originate from a non-AIN capable switch are forwarded to an AIN capable SSP in order to query said SCP.

### Claim 9 (depends on 8)

A method as defined in claim 8, wherein calls from non-AIN capable switches are forwarded to said AIN capable SSP, via an ISUP (Integrated Services Digital Network User Port) message containing a code indicative that the dialed number is directed to the VPDP.

### Claim 10 (depends on 9)

A method as defined in claim 9, wherein calls from non-AIN capable switches are forwarded to said AIN capable SSP, via a dedicated trunk connecting the non-AIN capable switches and said AIN capable SSP.

### Claim 11 (depends on 9)

A method as defined in claim 9, wherein calls from non-AIN capable switches are forwarded to said AIN capable SSP, via an ISUP parameter contained in said ISUP message.

### Claim 12

In a telephone network having a number of telephone switching offices equipped with SSPs (Service Switching Points) operating with AIN (Advanced Intelligent Network) application software, and a remotely located SCP(Service Control Point) adapted to receive, when required, SS7 (Signalling System 7) messages from the SSPs to translate a dialed number to enable the routing of a call on the telephone network, a method of routing a call according to a telephone number selected from a parallel, non-intrusive virtual public dial plan (VPDP), co-existing with the current network node address numbering plan, comprising the steps of:
a) receiving at one of the SSPs a series of DTMF codes including a dialed number;
b) determining whether the DTMF codes received include a VPDP access code, indicating that the dialed number is to be routed according to said VPDP; if the digits received include a VPDP access code:
i) forming, at said SSP, an SS7 message comprising the dialed VPDP number;
ii) sending the SS7 message from said SSP to said SCP along a common signaling channel;
iii) receiving the SS7 message at said SCP;
iv) translating the VPDP number in the SS7 message to a routing number corresponding to a telephone number associated with said existing network node address numbering plan; and
v) sending a response SS7 message from said SCP to said SSP, said SS7 message containing said routing number, such that the call can be routed on said telephone network; and
c) routing the call according to the current network node address numbering plan if the received DTMF codes do not include the VPDP Access Code.

### Claim 13 (depends on 12)

A method as defined in claim 12, wherein the step of determining comprises:
verifying whether the number dialed in step (a) is preceded by a predetermined prefix code indicative that the call is to be routed via the VPDP.

### Claim 14 (depends on 13)

A method as defined in claim 13, wherein the predetermined prefix code is used as an AIN trigger to instruct the SSP to form an SS7 message for sending to the SCP.

### Claim 15 (depends on 14)

A method as defined in claim 14, wherein the AIN trigger is a Public Office Dial Plan trigger.

### Claim 16 (depends on 14)

A method as defined in claim 14, wherein the AIN trigger is a customized dial plan trigger.

### Claim 17 (depends on 14)

A method as defined in claim 14, wherein the predetermined prefix code is deleted prior to forming the SS7 message.

### Claim 18 (depends on 17)

A method as defined in claim 17, wherein the predetermined prefix code is a character not used in the network node address numbering plan.

### Claim 19 (depends on 18)

A method as defined in claim 18, wherein the predetermined prefix code is the number (#) sign.

### Claim 20 (depends on 12)

A method as defined in claim 12, wherein calls directed to the VPDP, and which originate from a non-AIN capable switch are forwarded to an AIN capable SSP in order to query said SCP.

### Claim 21 (depends on 20)

A method as defined in claim 20, wherein calls from non-AIN capable switches are forwarded to said AIN capable SSP, via an ISUP (Integrated Services Digital Network User Port) message containing a code indicative that the dialed number is directed to the VPDP.

### Claim 22 (depends on 20)

A method as defined in claim 20, wherein calls from non-AIN capable switches are forwarded to said AIN capable SSP, via a dedicated trunk connecting the non-AIN capable switches and said AIN capable SSP.

### Claim 23 (depends on 20)

A method as defined in claim 20, wherein calls from non-AIN capable switches are forwarded to said AIN capable SSP, via an ISUP parameter contained in an ISUP message.

### Claim 24 (depends on 12)

A method as defined in claim 12, further comprising the step of verifying whether a customized code indicative of a predetermined subscriber station is appended to said dialed number.

### Claim 25 (depends on 24)

A method as defined in claim 24, wherein said customized code can be used to differentiate a first subscriber station from a second subscriber station.

### Claim 26

In a telephone network having a number of telephone switching offices equipped with SSPs (Service Switching Points) operating with AIN (Advanced Intelligent Network) application software, and a remotely located SCP(Service Control Point) adapted to receive, when required, SS7 (Signalling System 7) messages from the SSPs to translate a dialed number to enable the routing of a call on the telephone network, a system for routing a call according to a telephone number selected from a parallel, non-intrusive virtual public dial plan (VPDP), co-existing with the current network node address numbering plan, comprising:
a) a first SSP for receiving a series of DTMF codes including a dialed number;
b) means, at said SSP, for determining whether the DTMF codes received include a virtual public dial plan access code, indicating that the dialed number is to be routed according to said VPDP;
c) means for forming, at said SSP, an SS7 message comprising the dialed VPDP number, if the digits received include a VPDP access code;
d) an SCP for receiving said SS7 message from said SSP along a common signaling channel; and
e) means for translating the VPDP number in the SS7 message to a routing number corresponding to a telephone number associated with said existing network node address numbering plan such that the call can be routed on said telephone network.

### Claim 27 (depends on 26)

A system as defined in claim 26, wherein said virtual public dial plan access code comprises a predetermined prefix code indicative that the call is to be routed via the VPDP.

### Claim 28 (depends on 27)

A system as defined in claim 27, wherein the predetermined prefix code is used as an AIN trigger to instruct the SSP to form an SS7 message for sending to the SCP.

### Claim 29 (depends on 28)

A system as defined in claim 28, wherein the AIN trigger is a Public Office Dial Plan trigger.

### Claim 30 (depends on 28)

A system as defined in claim 28, wherein the AIN trigger is a customized dial plan trigger.

### Claim 31 (depends on 28)

A system as defined in claim 28, wherein the predetermined prefix code is deleted prior to forming the SS7 message.

### Claim 32 (depends on 31)

A system as defined in claim 31, wherein the predetermined prefix code is a character not used in the network node address numbering plan.

### Claim 33 (depends on 32)

A system as defined in claim 32, wherein the predetermined prefix code is the number (#) sign.