KR20000016424A - Call transfer operation - Google Patents

Abstract

PURPOSE: A call transfer operation is provided to prevent an objectless looping switching and an excess switching counts by rejecting further transfer of the call if a counter exceeds a given preset threshold. CONSTITUTION: Responsive to an incoming call (34) made to a primary telephone number subscribing to a call transfer calling service feature, a first switching node(12(1)) queries (36) a database (20) to retrieve (38) at least one transfer of secondary number. The first switching node then signals (46) other switching nodes (12) in the telephone network (10) to set up an outgoing leg (48) to each secondary number telephone. The signals transmitted by the first switching node further (50) direct each of the other switching nodes in the network to inhibit the initiation of any call transfer service features associated with the secondary number telephones. The signals may further include a transfer service indicator and a counter (80) identifying the number of prior call transfer which have occurred in connection with the originally received call. If the counter (80) exceeds a given preset threshold, the other switching nodes reject further transfer of the call.

Description

Call diversion operation

Today, many people have a work phone, a home phone and a mobile phone that they use when they are away from their office or home. Someone has multiple office and / or home phones that reconnect to a particular phone. It is common for telephone service providers to assign different phone numbers, unfortunately. To maximize the caller's chances to call the other party, he must look up the other party's phone numbers (home, office, and mobile phone numbers), and then dial in to these numbers. This manual method of looking up or calling a phone number is not satisfactory and is often inefficient in time.

One known solution to this problem is to use a call forwarding operation and specify the redirection of the call to the specified second number in response to the original call to the first number. The problem with this solution is that the call must be diverted to only one pre-determined number so that the person must know where he is in order to efficiently switch the next incoming call. Another drawback is that the phone associated with the first number is bypassed by the incoming call operation and this person cannot answer while the incoming call characteristic is initiated. Another drawback is that many of these systems are unable to take advantage of the remote initialization and non-energization of the call forwarding characteristics, so that they must have access to the phone of the first number to specify a new incoming second number.

Another known solution to this problem has to provide call handling equipment designated for the telephone. Using a second telephone or three-way calling feature, the designated equipment responds to an incoming call by simultaneously or sequentially alerting the called primary telephone or the remote (second) telephone designated by the subscriber. The call is connected to a first plurality of alerted telephones to be answered by the equipment. Problems with this solution include; Only a limited number of calls can be alerted. That is, expensive consumer-specific hardware settings and additional line or three-way calling characteristics at the primary call location are reserved.

Another solution to this problem is to use a telephone exchange in response to a call to the primary number by simultaneously and / or sequentially calling one or more designated secondary numbers. This is commonly referred to in the prior art as an incoming call switching characteristic and in particular a multi-leg call (multiple destination call). The exchange responds to the exchange by routing multiple telephone numbers of subscriber designations to incoming calls over a number of different hanging lags. When an outgoing call is received at the telephone switch, it can be seen that the primary number dialed by the call portion is associated with a multi-lag call. The first call connected to the hanging lag for the response is connected by the exchange to the incoming incoming call and the remaining hanging lag is disconnected.

Incoming outgoing calls during the control of a call exchange (not at the designated subscriber primary call location) provide flexibility in calling options and satisfactorily solve many of the problems associated with the aforementioned call handling and routing solutions. However, the telephone control call forwarding call has a problem of communication. One or more designated secondary numbers used to make an incoming / outgoing call in response to an incoming call to the primary number may be associated with its own attendant control service feature and may be able to initialize it. In many cases, however, it is undesirable to initialize these service characteristics in response to a call involving a lag in an incoming phone call. This is especially true for service features that provide another single or multi lag incoming call switching operation that follows the preceding incoming call operation.

For example, if a voice mail box is associated with a particular secondary number specified in the incoming call list associated with the primary number, incoming calls to the primary number that triggers the outgoing call transfer will not be connected (diverted) to the voice mail box of the secondary number. It may be desirable to be able to. Instead, it is desirable to first try another call option of call forwarding, and it is also desirable for any message to remain in the voice mail box associated with the originally called primary number instead. Therefore, a system and method for performing control on the initialization of a preceding call forwarding switching operation secondary number service characteristic should be provided.

The present invention relates to a telephone network, and more particularly, to a call forwarding to a secondary number in response to a call coming to a primary number through a telephone network, and also to perform control during the initiation of a secondary number service characteristic of such a call forwarding transition. It's about things.

1 is a simple block diagram of a telephone network with incoming call forwarding switching operation supported.

2 is a flow chart for call network operation and processing to prohibit secondary number incoming call transfer calling operations in accordance with the present invention.

3 is a flow chart for telephone network operation and call processing to limit incoming call forwarding operations in accordance with the present invention.

In a telephone network comprising a plurality of switched nords, one first switched nord receives an incoming call dialed to the primary telephone number. In response to an incoming call, the first switched norwood determines whether the phone is associated with a primary number subscriber for an outgoing call forwarding service characteristic (such as an incoming or multi-lag call). In the case of yes, one or more secondary telephone numbers which have been received full-time are received from the database. The first switched nord is then diverted to another switched nord of the telephone network over a signal link to establish one or more hanging lags connected to the telephone associated with the secondary telephone number received on the voice trunk. The transmitted command includes a control command for another switching nord to prohibit the initiation of any outgoing call forwarding service characteristic associated with the secondary telephone to the transmitted call.

Alternatively, this control command includes a call forwarding prohibition feature identifier and a redirection information counter that identifies the number of the preceding call forwards that occurred with respect to the originally received call. If this counter exceeds a predetermined preset threshold, the switching nord rejects another incoming call transfer. This property serves to prevent unwanted looping transitions or excessive numbers of transitions.

1 is a schematic diagram illustrating a telephone network 10 including a plurality of interconnected switched norms (SN) 12. Switchboard Norwood 12 includes one of a number of known telecommunication switching devices for providing a digital or analog ground line or cellular telephone service to one of a plurality of subscriber telephones 14, which is generally known in the prior art. have. The switching norms 12 are interconnected to communicate via both the signal link 16 and the voice trunk 18. Voice trunk 18 provides voice and data communication paths that are used to switch subscriber communications between the nodes 12. The signal link 16 switches command signals between the nodes 12 to establish and destroy voice and data communications over the voice trunks 18 and to request and control specific service characteristics for the subscribers 14.

The exchange nord 12 is connected to the database 20 (or multiple databases, if necessary) by a signal link 16. For example, the signal link 16 switches the command signal to locate and pre-route the subscriber. In the case of a landline network, the database 20 includes an exchange control point database. In the case of a cellular telephone network, the database 20 includes a home location register to which the telephone number of the called mobile station is assigned.

The database 20 stores information about subscriber telephone 14, including subscriber telephone numbers relating to the identification of any service characteristics registered for use by subscribers associated with the telephone number. These service features include call waiting, three-way calling, paging, voice mail, call forwarding, and mulit-leg calling. This latter service characteristic includes an example of an incoming / outgoing switching service characteristic. Similarly, the network comprises one or more databases 20 and a number of databases (not shown) in this network, as described above, are single links (such as link 16) that divert command signals used for the same purpose. It can be seen that they are interconnected by.

For an example of an incoming call forwarding service, the voice mail feature includes a selection and preference for retrieving the last subscriber of the recorded voice message in response to an incoming call to the subscriber's telephone number. Incoming call forwarding service features include automatic forwarding of calls to the subscriber's telephone number for another number designated by the subscriber. The multi-lag service feature includes calling a plurality of subscriber specified numbers in either a simultaneous or sequential manner in response to a number coming to the subscriber's telephone number. Other types of incoming call forwarding service characteristics are known in the prior art.

A telephone exchange nord 12 and a database 20 connected thereto capable of implementing incoming call forwarding service characteristics for a landline or cellular subscriber are known in the prior art. For example, US Pat. No. 5,206,901 to Harlow et al. Discloses a method and apparatus for executing a multi lag call by alerting multiple telephones to an incoming call. The attendant Norwood 12, which handles the incoming call, searches the database 20 to retrieve the routing instructions for the call, including the confirmation of the number of calls that should be alerted. In response to one of the confirmed phones answering the alert, the incoming call is connected to the answering phone and other potential connections are lost. In order to implement the multi-log service feature, the multiple telephones identified in the routing instructions do not need to be serviced by the same switching node 12 receiving the initial incoming call and initiating the multi lag call. Moreover, designated service norwood can be used if necessary. The multiple telephones identified in the routing command can be alerted by the telephone exchange node 12 simultaneously or sequentially during the multi-lag calling operation, depending on the desire of the called party. Call forwarding and voice mail switching are known in the art.

It will be clearly understood by referring to specific examples of unknown multi-lag calling behavior. A telephone call to the primary number (associated with the telephone part 30 of the called part) was said to have originated in the calling part from the telephone 32 and started in the exchange nord 12 (1). In response to the receipt of this incoming call (over the incoming lag 34), the database (in order to be called by a signal switched from the initial database to other databases, if necessary) to locate the called mobile subscriber ( 20) and determine which service characteristics the called party subscribes to. The retrieved property 38 is processed by the exchange nord 12 (1) to further process the next incoming call.

If one of the retrieved service properties 38 includes a multi lag call, the multiple lag routing commands, including the list of called secondary telephone numbers, as well as the search for instructions as to whether to perform sequential or simultaneous calls. More in response is provided. Similar routing instructions are retrieved or voice mail is diverted when the service characteristic 38 includes call forwarding. The list of secondary numbers says that they identify phones 40, 42 and 44 for multi-lag calls. The exchange nord 12 (1) is connected to the telephones 40, 42, 44 associated with the listed secondary number and alerts multiple hanging lags 48 (sequentially or At the same time, the command 46 is switched to the other nord 12 over the signal link 16. The first of the telephones 40, 42, 44 to be answered is picked up by the switching nord 12 (1) via a hanging lag 48 to complete the call connection between the calling party and the called party. Coming lag 34.

It should be noted that one or more telephones identified in the call forwarding service personality routing command may connect themselves to the incoming call forwarding service personality and call forwarding service personality routing commands such as voicemail, call forwarding, and multi-lag calls. Can be. When such a call includes a primary number for an incoming call, initialization of the subscriber select service feature is performed by the switching nord 12. On the other hand, when the telephone includes a secondary number called in connection with the provision of an incoming call forwarding call operation, it is not always desirable for the incoming call forwarding service characteristic to be disclosed.

In order to perform this control in response to the initiation of the outgoing call service feature during the outgoing call forwarding operation, the exchange nord 12 will display the incoming call lag of the transmitted call and the database 12 for the called second number. In order to transmit over the signal link 16 (including the IS-4 and CCITT / ANSISS7 TUP / ISUP protocol links) specifying that no incoming service characteristics related to Parameters) are configured to issue a control command 50. The exchange norwood 12 responds to the receipt of the command 46 by connecting to the voice trunk and alerting the telephone associated with the called secondary number. In response to the control command 50, the analysis of the database 20 of the secondary number to confirm the incoming call forwarding service characteristics, since the call being processed is part of the preceding (and limited) incoming call forwarding operation, the exchange node. It is not made by the wood 12. However, the exchange nord 12 may continue to provide other service characteristics (such as call waiting or three way calling) and not perform a call transfer to the called secondary telephone number during a transferred call. If the call does not answer, the exchange nord 12 stops and returns control of the call that returns to the exchange nord when an incoming call is received (preferably originally received).

The execution of control by the exchange norwood on the initiation of the secondary telephone service characteristic using the message 50 will be clearly seen by referring back to the previously mentioned multi-lag call. The exchange nord 12 (1) receives a list of secondary telephone numbers to be called as well as instructions as to whether sequential or simultaneous calls should be made (multi lag routing instructions). In this example, the list of secondary phone numbers identifies phones 40, 42, 44 for multi lag calls. The exchange norwood 12 (1) then commands a number of hanging lags 48 on the voice trunk 18 to alert the connected trunk 40, 42, 44 associated with the listed secondary number. Switch 46. As a parameter in the command, the exchange nord 12 (1) is responsible for any call forwarding service in which the calling lag 48 of the multi-lag call is associated with the called secondary number 40, 42, 44 and the database 20. Toggle the control command 50, which specifies not to cause a characteristic. Thus, if the database 20 records the voicemail call diversion service characteristics associated with the telephone 40, these characteristics are performed by the exchange nord upon receipt of the hanging lag 48 (1) of the multi-lag call. It doesn't work. Similarly, if the database 20 records incoming call forwarding service characteristics associated with the telephone 42, in the case of reception of the hanging lag 48 (2) of the multi-lag call, the database 20 (4) This characteristic is not performed by this. Furthermore, if the database 20 records the multi lag call service characteristics associated with the telephone 44, the reception of the hanging lag 48 (3) of the multi lag call initiated by the exchange nord 12 (1). In the city, this characteristic is performed by the exchange nord 12 (2). As mentioned above, the first of the telephones 40, 42, 44 to be answered is then switched to the exchange norwood 12 (1) via the associated hanging lag 48 to complete the call connection between the calling party and the called party. ) Is connected to the incoming lag 34.

Figure 2 shows a flow diagram for telephone network operation during a call diversion call operation with controlled secondary number service characteristics, in accordance with the present invention. A call to the primary number over the incoming lag is made in step 60 and received by the exchange nord in step 62. This network is not successful in attempting to divert the call to the primary subscriber. This failure may be indicated by a time-out, an IS-41 redial request or an ISUP call release message. The switching nord then determines, in step 64, whether the called portion is associated with the dialed primary number subscriber for the calling service characteristic. If not determined, the incoming call is handled in a manner known to those skilled in the art (step 66). If it is determined to be relevant, the exchange nord in step 68 to search for instructions relating to the multi-lag call, as well as routing instructions including secondary numbers to which the call is diverted, as well as sequential or concurrent calls. Search the database. The message is diverted in step 70 to the remaining switching norms of the network over the included signaling link to establish one or more hanging lags over the voice trunk for the secondary number's phone. The control message is also diverted to step 72 (separate from the parameters in the message at step 70) directed to each switching norm to prohibit the initiation of any call transfer service characteristic associated with the secondary telephone. This message includes a divert counter service identifier identifier parameter if necessary. The call to the secondary number is alerted in step 74. The exchange nord and incoming call following the test at step 76 of the answering of the alerted call is completed at step 78 and is connected to the answering secondary telephone.

Referring back to FIG. 1, in order to perform initialization of the call transfer service characteristic during the incoming call forwarding call operation, the exchange nord 12 maintains a track of the call transfer operation initialized in response to the original incoming call and controls commands. It is configured to store the number of the previously executed call transfer tracked at the counter 80 associated with (50). Command 50 and counter 80 are sent for signal link 16 including (IS-41 and CCITT / ANSISS7 TUB / ISUP protocol links). The exchange nord 12 responds to the receipt of the counter 80 by comparing the stored call transfer value with the transpose threshold. If the memorized value exceeds the threshold, the analysis of the secondary number database 20 to verify the call forwarding service characteristics, since the call is already diverted by the system deemed it takes too much time, Performed by wood 12.

However, the exchange norwood 12 will continue to provide the called secondary number phone during the transmitted call other miscellaneous service characteristics (such as call waiting or three way calling) that do not imply a call diversion.

Execution of the control by the switching nord with respect to the start of the secondary telephone service characteristic using the counter 80 may be understood by referring again to the above-described heavy lag call example. Switchboard 12 (1) receives a list of secondary telephone numbers that should be called and instructions as to whether sequential or simultaneous calls are performed. In this example, the list of secondary telephone numbers identifies the telephones 40, 42, 44 for multi lag calls. Switchboard 12 (1) connects multiple hanging lags 48 (sequentially or through voice trunk 18) to connect and alert to telephones 40, 42, 44 associated with the listed secondary number. At the same time, the command 46 is switched to the remaining nord 12 via the signal link 16 for setting. Implementing or with parameters in the command 46, the exchange nord 12 (1) causes the hanging lag 48 of the multi-lag call to have one value (indicating that only a single transmission has been initiated for the original call). The control command 50 is further switched to specify that the counter 80 having the call and the called secondary number 40, 42, 44 and the database 20 do not cause any related call transfer service characteristics. Now, the exchange nord 12 (3) has not been ignored (via a process error) or upgraded in response to a prohibition order 50. Thus, if database 20 records an incoming call forwarding service characteristic (designating telephone 42) associated with telephone 40, this characteristic will be improperly executed by exchange norwood 12 (3). . The command 46 is then switched to set the hanging lag for the exchange nord 12 (4). In addition to or with the parameters in command 46, exchange norm 12 (1) is a counter 80 with two values indicating that control command 50 and (the second transfer has been initiated for the original call). In response to receiving the diverted call, the exchange nord 12 (4) compares the value of the counter 80 with a transpose threshold, if this threshold is 1, the counter value exceeds this threshold. And the exchange nord 12 (4) does not perform more call transfer service characteristics.

Figure 3 shows a flow chart for telephone network operation during an incoming / outgoing switching operation by controlled secondary number service initialization according to the present invention. The call to the primary number through the incoming lag is received by the switching nord at step 84 beginning at step 82. This failure may be indicated by a time-out or an IS-41 redial request or an ISUP call release message. The exchange nord determines in step 86 whether the called party associated with the dialed primary number subscribes to the outgoing call service characteristic. If not, the incoming call is handled in a manner known to those skilled in the art (step 88). If relevant, the exchange nord searches the database at step 90 to retrieve a routing instruction that includes the secondary forwarding number. To establish one or more hanging lags by dialing the second number's phone to a voice trunk, the message is diverted in step 92 to the other switching norms of the network for the included signal link in accordance with the retrieved routing instructions. The counter and service indicators are switched in step 94, which identifies the number of the transmission that was performed for the originally received call (separate from the message as a parameter in step 92). Such transmission prohibition may also be initiated by call. The exchange nord then tests in step 96 whether the call transfer is initiated by a call. If not initiated, then step 98 is processed in a conventional manner (via the initialization or response of other call services). If initiated, the exchange nord tests in step 100 whether the counter value exceeds the transposition threshold. If not initiated, processing returns to step 90 to perform a switchover and the counter value is incremented by one to prevent the occurrence of additional transmissions. If initiated it is prohibited in step 102.

An advantage of the use of the counter 80 to detect an incoming / outgoing call is that the call transfer looping can be prevented. By sensing the value of the counter 80, the exchange nord can exit from many numbers recorded therein. This number is where the call in question is related to a qualified loop of transmissions (ie, A designates B as a forward subscriber, C designates a forward subscriber, and C designates A as a forward subscriber). This phenomenon must be stopped, the exchange nord must be sustained to provide other service characteristics (such as call waiting or three-way calling), or limited looping of the transmitted call is being called by one or more exchange norwoods. It occupies all circuits quickly, causing exchange congestion.

In connection with one embodiment of the present invention, existing messages and parameters set up for use within a digital telephone network may be adopted and possibly employed to provide and use control messages 50 and counters 80. For example, in the case of a digital terrestrial telephone network, the existing integrated service digital network user part (ISDN-UP) message initial address message (IAM) secondary number telephone call transfer service for signaling link is prohibited. Prohibit necessary identifiers (including control message 50 and counter 80) and redirection information. Furthermore, in the case of cellular telephone networks, these parameters may be used for the location switching, numbering, and routing requests for a single switched node of these instances in connection with an outgoing call forwarding operation where secondary number call forwarding service characteristics are not prohibited. Messages, such as messages).

Although preferred embodiments of the method and apparatus of the present invention are described in the accompanying drawings and the detailed description of the invention, the present invention is not limited to the disclosed embodiments and is rearranged and modified with heat without departing from the spirit of the invention as defined by the following claims. And it should be understood that replacement is possible.

Claims (33)

A method for controlling the initiation of a secondary telephone service characteristic during a call transfer call operation, Retrieving one or more secondary telephone numbers associated with the primary telephone number in response to receiving a telephone call dialed to the primary telephone number subscribed to the call transfer service feature; Establishing a forwarding call to a telephone of each retrieved plurality of secondary telephone numbers via at least one exchange nord; Signaling each switched norm in connection with not setting up a call to use a service characteristic associated with a secondary number telephone. 2. The secondary number telephone service according to claim 1, wherein the transmission call comprises a multi lag call and the setting step includes setting the multi lag call to a telephone of a plurality of secondary telephone numbers searched in a sequential manner. A method of controlling the onset of a characteristic. 2. The secondary number telephone service feature of claim 1, wherein the forwarding call comprises a multi lag call and the step of setting up comprises setting a multi lag call to a telephone of a plurality of secondary telephone numbers retrieved in a simultaneous manner. To control the initiation of the reaction. 2. The method of claim 1, wherein the service characteristic associated with the secondary number telephone comprises a call diversion service characteristic. 5. The method of claim 4, wherein the call forwarding service characteristic comprises an incoming operation from the secondary number telephone to another telephone. 5. The method of claim 4, wherein the call forwarding service feature includes voice mail transition from the secondary phone to the voice mail box. 5. The method of claim 4, wherein the call forwarding service feature comprises a multi-lag call operation starting from the secondary number phone. A first exchange nord that receives an incoming call dialed to a primary number that subscribes to a call diversion call service feature; and a plurality of interconnected exchange nouns including one or more second exchange nords to which a diversion call is assigned; ; And wherein the first exchange norwood signal of each second exchange norwood associated with the call forward is set to be inactive for the transfer call service characteristic associated with the secondary number telephone. 10. The method of claim 8, wherein the forwarding call comprises a multi-lag call set up by the first and second exchange norwood identified by the secondary phone in a sequential manner. Way. 10. The method of claim 8, wherein the forwarding call comprises a multi-lag call set up by the first and second exchange norwood identified by the secondary phone in a concurrent manner to control the initiation of the secondary phone service. Way. 10. The method of claim 8, wherein the service characteristic associated with the secondary number telephone comprises a call diversion service characteristic. 12. The method of claim 11, wherein the call divert service characteristic comprises an incoming call from the secondary number telephone to another telephone. 12. The method of claim 11, wherein the call forwarding service feature includes the voice mail transition from the secondary phone to the voice mail box. 12. The method of claim 11, wherein the call transfer service feature comprises a multi-lag call operation originating from a secondary number telephone. Multiple exchange norwoods; A plurality of voice trunks connecting a plurality of exchange nords; It has a plurality of signal links connecting a plurality of exchange norms, The originating norwood of one of the switched norwoods switches over the signaling link to the remaining switched norwoods to set up the divert call on the voice trunk and the signal to prevent the initiation of service related to the destination telephone during the outgoing call period. A telephone system comprising a control command for instructing a switched norwood. 16. The telephone system according to claim 15, wherein the telephone system is a cellular telephone system. 16. The telephone system according to claim 15, wherein the service characteristic includes an incoming call from a destination telephone to another telephone. 16. A telephone system according to claim 15, wherein the service characteristic includes an incoming call from a destination telephone to another telephone. 16. The telephone system of claim 15, wherein the service characteristic comprises multi-lag calls originating from the destination telephone. A method in which one or more hanging call lags control service feature initiation during a call transfer call operation established on a destination telephone through one or more switching norms, Transmitting a command control signal as part of a transmission call during call setup to identify an outgoing call lag; During this transmission call period, each call prohibiting the initiation of a call transmission service characteristic associated with a destination telephone connected to the call lag at each switching node receiving the transmitted command control signal. How to control. 21. The method of claim 20, wherein the call forwarding service feature includes an incoming operation from a destination telephone to another telephone. 21. The method of claim 20, wherein the call forwarding service feature includes voice mail switching from the destination telephone to the voice mail box. 21. The method of claim 20, wherein the call transfer service feature comprises a multi-lag call originating from a destination telephone. Retrieving at least one secondary telephone associated with the telephone number in response to receiving a telephone call for the telephone number subscribed to the call transfer service feature; Setting up a transfer call via one or more exchange norms on the telephones of the plurality of retrieved secondary telephone numbers; Signaling each switched norm in connection with setting up a transfer call to a counter identifying a number of a preceding call transfer associated with a telephone call; Comparing the call transfer number from the counter with a threshold value and prohibiting the switching of the telephone call if the counter number exceeds the threshold. How to. 25. The method of claim 24, wherein the service feature associated with the secondary phone includes a telephony service feature. 27. The method of claim 25, wherein the call forwarding service feature comprises an incoming call from the secondary number telephone to another telephone. 27. The method of claim 25, wherein the telephony service feature comprises a voice mail transition from a secondary phone to a voice mail box. 27. The method of claim 25, wherein the call transfer service feature comprises a multi-lag call operation originating from a secondary number phone. Multiple exchange norwoods; A plurality of voice trunks connecting the plurality of exchange norms; A plurality of signal links connecting the plurality of exchange norms; The Norwood currently in process of the switched nord switches the signal over the signal link to the other one of the switched nords in order to set up the outgoing call on the voice trunk, and this signal is transmitted to the preceding call associated with the outgoing call. A counter identifying the number of the telephone system, wherein the counter is blocked by the remaining switching nord to prohibit the initiation of service characteristics associated with the destination telephone if the call transfer number exceeds the transposition threshold. . 30. The telephone system according to claim 29, wherein the telephone system is a cellular telephone system. 30. The telephone system according to claim 29, wherein the service characteristic includes an incoming call from a destination telephone to another telephone. 30. The telephone system as recited in claim 29, wherein the service feature includes voice mail switching from the destination telephone to the voice mailbox. 30. The telephone system as recited in claim 29, wherein the service characteristic comprises a multi lag call originating from a destination telephone.