# US 7,106,842 B2 · Method of detecting cut-off calls in a switching system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,106,842 B2 - Document ID: US7106842B2 - Status: Granted - Kind: B2 - Application number: 10/247,296 - Filed: 2002-09-20 - Published: 2003-03-27 - Granted: 2006-09-12 - Earliest claimed: 2001-09-27 - Assignees: LG Electronics Inc. - Inventors: Sang Yup Lee - Web page: https://patentgrep.com/patent/US7106842B2 ## CPC - H04M 15/74: {Backing up} - H04M 3/22: Arrangements for supervision, monitoring or testing - H04M 15/00: Arrangements for metering, time-control or time indication {; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP} - H04M 15/58: {based on statistics of usage or network monitoring} - H04Q 1/20: Testing circuits or apparatus; Circuits or apparatus for detecting, indicating, or signalling faults or troubles - H04M 3/10: Providing fault- or trouble-signals - H04M 2215/0188: Network monitoring; statistics on usage on called/calling number - H04M 2215/709: Backup - H04Q 2213/13092: Scanning of subscriber lines, monitoring - H04Q 2213/13103: Memory - H04Q 2213/13106: Microprocessor, CPU - H04Q 2213/13166: Fault prevention - H04Q 2213/13209: ISDN - H04Q 2213/1327: Release and resetting of connection - H04Q 2213/13272: Premature release - H04Q 2213/13294: CDMA, code division multiplexing, i.e. combinations of H04Q2213/13291 and/or H04Q2213/13292 with space division - H04Q 2213/1337: Operator, emergency services - 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 system and method for detecting cut-off of calls in a switching system records data corresponding to connection of a call in a first memory, records the call connection data in a second memory, and then at a later time and, for example, in response to a call release request compares the data in the two memories corresponding to the call. If the data does match, it is determined that the call has been cut-off. The first memory may be located in a switching unit and the second memory may be located in a processor which controls the switching unit. The switching unit may be a time switch or a space switch. Once a call cut-off is detected, the processor transmits information notifying an operator of the cut-off. The system and method represents an improvement over existing systems in terms of increased reliability and ease of repair and maintenance of system components. ## Claims ### Claim 1 A method of detecting cut-off calls in a switching system, comprising: recording data corresponding to connection of a call in a first memory device based on a call connection request, said call connection data including control memory address and control memory data for performing the call connection request; recording the call connection data in a second memory device; determining whether a cut-off call has occurred in response to a call release request, said determining including comparing the call connection data including the control memory address and the control memory data stored in the second memory device with current call connection data including control memory address and control memory data corresponding to the call stored in the first memory device; and notifying an operator if a cut-off call has been determined to have occurred. ### Claim 2 (depends on 1) The method of claim 1, wherein the first memory device is a control memory provided in a switch device. ### Claim 3 (depends on 1) The method of claim 1, wherein the second memory device is an internal memory provided in a switch control processor. ### Claim 4 (depends on 1) The method of claim 1, further comprising: detecting that the call connection data stored in the first memory has been changed as a result of a cut-off of the call, said changed call connection data corresponding to the current call connection data stored in the first memory device. ### Claim 5 (depends on 1) The method of claim 1, wherein the notifying comprises: transmitting cut-off call occurrence information to a main processor, said cut-off call occurrence information indicating that a cut-off call has occurred at the call for which the call release has been requested; and formatting the cut-off call occurrence information at the main processor in a form that maybe recognized by the operator, and notifying the operator of the cut-off call occurrence based on the cut-off occurrence information. ### Claim 6 (depends on 1) The method of claim 1, further comprising: releasing the call by recording data needed for call release in the first memory device if no cut-off call has occurred. ### Claim 7 A method of detecting cut-off calls in a switching system, comprising; recording data corresponding to connection of a call in a control memory in a switch device and within an internal memory in a switch control processor based on a call connection request, said call connection data including control data for performing the call connection request; determining, in response to a call release request, whether current data including control data recorded in a location of the control memory used to store the call connection data at the time of connecting the call is identical to the data including the control data which was recorded in the internal memory of the switch control processor at the time of connecting the call; and if the data are not identical, notifying an operator that a cut-off call has occurred. ### Claim 8 (depends on 7) The method of claim 7, wherein the recording includes: searching for an idle area in the control memory according to a call connection request; formatting the call connection data in a form appropriate for recording in the control memory; connecting the call by recording the formatted data in the searched area of the control memory; and recording the call connection data recorded in the control memory in the internal memory. ### Claim 9 (depends on 7) The method of claim 7, wherein the determining comprises: searching for an idle area of the control memory according to a call release request; formatting the call connection in a form appropriate for recording in the control memory; reading the data recorded in the location of the control memory used to store the call connection data at the time of connecting the call; and comparing the read data with the data recorded in the internal memory of the switch control processor, and determining whether these data are identical. ### Claim 10 (depends on 7) The method of claim 7, wherein the notifying comprises: determining that a cut-off call occurred if the current data stored at the location of the control memory used to store the call connection data is not identical to the data recorded in the internal memory at the time of connecting the call; transmitting to a main processor cut-off call occurrence information according to a result of the determination; and formatting the cut-off call occurrence information at the main processor in a form that maybe recognized by the operator, and notifying the operator of the cut-off call occurrence with the formatted information. ### Claim 11 (depends on 7) The method of claim 7, further comprising: releasing the call by recording the formatted data in the searched area of the control memory according to the call release request, if it is determined that the two data are identical. ### Claim 12 (depends on 7) The method of claim 7, wherein the switching device is either a time switch or a space switch. ### Claim 13 (depends on 7) The method of claim 7, wherein the data needed for call connection comprises: control memory address which includes data writing/reading information, output channel, and sub-highway information; and control memory data which includes busy/idle information regarding use of the control memory address, input channel, and sub-highway information. ### Claim 14 A method for detecting cut-off calls in a switching system, comprising: storing data corresponding to connection of a call in a first memory, said call connection data including control information required for establishing the connection of the call; detecting a change in said call connection data stored in the first memory; and determining that the call has been cut-off based on said detected change, wherein said detecting includes: storing said call connection data in a second memory; comparing current data including control information stored in the first memory and corresponding to connection of the call with said call connection data including the control information stored in the second memory; and detecting that a change in said call connection data has occurred based on results of said comparing. ### Claim 15 (depends on 14) The method of claim 14, wherein said storing includes storing said call connection data in a location in the first memory, and wherein said detecting includes detecting whether the current data including the control information stored at said location is the same as said call connection data including the control information. ### Claim 16 (depends on 14) The method of claim 14, wherein the first memory is in a switch device. ### Claim 17 (depends on 16) The method of claim 16, wherein the switch device is a time switch. ### Claim 18 (depends on 16) The method of claim 16, wherein the switch device is space switch. ### Claim 19 (depends on 14) The method of claim 14, wherein the second memory is in a processor which controls the switch device. ### Claim 20 (depends on 14) The method of claim 14, further comprising: notifying an operator that the call has been cut-off. ### Claim 21 A system for detecting cut-off calls in a switching system, comprising: a call switching unit having a first memory, said first memory storing data corresponding to connection of a call, said call connection data including control memory address and control memory data for performing the call connection request; and a controller which detects a change in said call connection data stored in said first memory, and determines that the call has been cut-off based on said detected change, wherein the controller stores said call connection data in a second memory, compares current data including control memory address and control memory data stored in said first memory and corresponding to connection of the call with said call connection data including the control memory address and the control memory data stored in the second memory, and detects that a change in said call connection data has occurred based on said comparison. ### Claim 22 (depends on 21) The system of claim 21, wherein said first memory stores said call connection data in a location in the first memory, and wherein the controller detects whether the current data including the control memory address and the control memory data stored at said location is the same as said call connection data including the control memory address and the control memory data. ### Claim 23 (depends on 21) The system of claim 21, wherein the second memory is stored in said controller. ### Claim 24 (depends on 21) The system of claim 21, wherein said first memory is in a switch device. ### Claim 25 (depends on 24) The system of claim 24, wherein the switch device is a time switch. ### Claim 26 (depends on 24) The system of claim 24, wherein the switch device is space switch. ### Claim 27 (depends on 21) The system of claim 21, wherein the controller notifies an operator that the call has been cut-off.