US009225838B2
`
`(12) United States Patent
`Hodge et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 9,225,838 B2
`Dec. 29, 2015
`
`(54) SYSTEM AND METHOD FOR DETECTING
`THREE-WAY CALL CIRCUMVENTION
`ATTEMPTS
`
`(71)
`
`(72)
`
`Applicant: Value-Added Communications, Inc.,
`Reston, VA (US)
`
`Inventors: Stephen L. Hodge, Aubry, TX (US);
`Fred Kesterson, Parker, TX (US); Serge
`Seyfetdinov, Plano, TX (US)
`
`(73)
`
`Assignee: Value-Added Communications, Inc.,
`Plano, TX (US)
`
`(*)
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 18 days.
`
`(21)
`
`Appl. No.: 13/958,137
`
`(22)
`
`Filed:
`
`Aug. 2, 2013
`
`(65)
`
`(63)
`
`(51)
`
`(52)
`
`(58)
`
`Prior Publication Data
`
`US 2013/0322614 A1
`
`Dec. 5,2013
`
`Related U.S. Application Data
`
`Continuation-in-part of application No. 12/378,244,
`filed on Feb. 12, 2009, now Pat. No. 8,630,726.
`
`Int. Cl.
`
`H04M 3/22
`H04M 3/20
`H04M 3/56
`H04M 3/42
`U.S. Cl.
`
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`
`CPC .............. .. H04M3/56 (2013.01); H04M3/205
`(2013.01);H04M3/2281(2013.01);H04M
`3/42314 (2013.01); H04M2203/6027 (2013.01)
`Field of Classification Search
`CPC ..... .. H04M 3/2281; H04M 3/38; H04M 1/82;
`H04M 1/68; H04M 1/67; H04M 15/47;
`H04M 3/2272; H04M 2203/6027
`
`USPC ................ .. 700/94, 381/58; 379/2, 22.03, 24,
`379/29.03, 93.02, 114.14, 168, 189, 199,
`379/207.06, 377
`See application file for complete search history.
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`4,670,628 A
`4,691,347 A
`4,737,982 A
`4,813,070 A
`
`6/1987 Boratgis et al.
`9/1987 Stanley et al.
`4/1988 Boratgis et al.
`3/1989 Humphreys et al.
`
`(Continued)
`
`FOREIGN PATENT DOCUMENTS
`
`GB
`JP
`
`2075 313 A
`59225626 A
`
`11/1981
`12/1984
`
`(Continued)
`OTHER PUBLICATIONS
`
`Bender, W., et a1., “Techniques for Data Hiding,” IBM Systems
`Journal, Vol. 35, Nos. 3&4, 1996.
`
`(Continued)
`
`Primary Examiner — Jesse Elbin
`(74) Attorney, Agent, or Firm — Sterne, Kessler, Goldstein
`& Fox PLLC
`
`(57)
`
`ABSTRACT
`
`Disclosed is a three-way call detection system and method for
`use with a telephone management system. Specifically, a
`three-way call detection system and method for detecting
`continuous noise indicative ofan attempt to mask a three-way
`call attempt. The continuous noise detection system and
`method may be stand alone or used in conjunction with any
`existing three-way call detection system and method.
`
`20 Claims, 7 Drawing Sheets
`
`50,
`
`
`
`Allowed‘?
`
`513
`
`No
`
`/
`
`93'‘
`
`E
`517
`
`
`
`511
`
`Silence
`Detected?
`
`
`
`
`
`ND
`
`
`
`Minimum
` Threshold
`
`Exceeded?
`V55
`Stream:
`
`507
`509
`
`
`No
`
`Page 1
`
`SECURUS EXHIBIT 1001
`
`SECURUS EXHIBIT 1001
`
`Page 1
`
`

`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,907,221 A
`4,918,719 A
`4,943,973 A
`4,995,030 A
`5,291,548 A
`5,319,702 A
`5,319,735 A
`5,345,595 A
`5,379,345 A
`5,425,091 A
`5,438,616 A
`5,502,752 A
`5,535,194 A
`5,535,251 A
`5,539,731 A
`5,539,812 A
`5,555,551 A
`5,583,925 A
`5,590,171 A
`5,592,548 A
`5,513,004 A
`5,619,561 A
`5,534,085 A
`5,535,292 A
`5,540,490 A
`5,545,940 A
`5,549,050 A
`5,687,236 A
`5,710,834 A
`5,719,937 A
`5,745,558 A
`5,745,569 A
`5,745,504 A
`5,748,725 A
`5,748,753 A
`5,748,783 A
`5,757,889 A
`5,768,355 A
`5,758,425 A
`5,774,452 A
`5,796,811 A
`5,805,585 A
`5,822,432 A
`5,822,435 A
`5,832,119 A
`5,835,486 A
`5,841,885 A
`5,841,978 A
`5,850,481 A
`5,852,250 A
`5,857,552 A
`5,883,945 A
`5,889,558 A
`5,899,972 A
`5,907,502 A
`5,920,834 A
`5,925,533 A
`5,930,359 A
`5,930,377 A
`5,953,049 A
`5,950,080 A
`5,953,909 A
`5,982,891 A
`5,999,828 A
`5,011,849 A
`5,025,193 A
`6,035,034 A
`6,052,462 A
`6,064,963 A
`6,072,860 A
`6,078,567 A
`6,078,645 A
`6,111,954 A
`6,122,392 A
`6,122,403 A
`
`3/1990 par1an1e1a1,
`4/1990 Daudelin
`7/1990 Werner
`2/1991 He1f
`3/1994 Tsumura et al.
`5/1994 Knehin
`6/1994 Preussetal.
`9/1994 Johnson et al.
`1/1995 Greenberg
`5/1995 Josephs
`8/1995 Peoples
`3/1995 Andrew e1 31,
`7/1996 Ashleyetal.
`7/1995 Brown e131,
`7/1996 Hanedaetal.
`7/1995 Knehin
`9/1996 Rudokasetal.
`12/1996 Bernstein
`12/1996 Howe etal.
`1/1997 S111
`3/1997 Cooperrnan
`4/1997 Reese
`5/1997 Rt1seheVeta1,
`5/1997 Rhoads
`5/1997 Hansen e131,
`7/1997 H0110
`7/1997 E110Zye1a1,
`11/1997 Moskowitz et al.
`1/1998 Rhoads
`2/1998 Warrenet al.
`4/1998 Richardson, Jr.
`4/1998 Moskowitz et al.
`4/1998 Rhoads
`5/1998 Unne
`5/1998 Rhoads
`5/1998 Rhoads
`5/1998 Qhtake
`6/1998 Salibrici
`5/1998 Rhoads
`5/1998 W010seW1eZ
`8/1998 McFar1en
`9/1998 Me1:ar1en
`10/1998 Moskowitz et al.
`10/1998 Rhoads
`11/1998 Rhoads
`11/1998 Davis etal.
`11/1998 Rhoads
`11/1998 Rhoads
`12/1998 Rhoads
`1/1999 Rhoads
`2/1999 geherer
`3/1999 Richardson, Jr.
`3/1999 Serap1nrneta1,
`5/1999 M1yaZaWae1a1,
`5/1999 pee1e1a1,
`7/1999 S111 e131,
`7/1999 Gainsbere
`7/1999 COX e131,
`7/1999 p0We11e1a1,
`9/1999 Horn et 31,
`9/1999 1:ah1rnane1a1,
`10/1999 Warrene1a1,
`11/1999 G1ntereta1,
`12/1999 S111 e131,
`1/2000 Orrin
`2/2000 Rhoads
`3/2000 Trump
`4/2000 Lu
`5/2000 Gainsboro
`6/2000 Kek et a1.
`6/2000 Traillet al.
`6/2000 Caiet al.
`8/2000 Rhoads
`9/2000 Rhoads
`9/2000 Rhoads
`
`Page 2
`
`US 9,225,838 B2
`Page 2
`
`6,138,119 A
`6,141,406 A
`6,185,416 B1
`6,185,683 B1
`6,205,249 B1
`5,233,347 B1
`6,237,786 B1
`6,243,480 B1
`6,243,676 B1
`6,253,193 B1
`6,263,507 B1
`6,266,430 B1
`6,278,772 B1
`6,278,781 B1
`5,289,108 B1
`6,301,360 B1
`6,312,911 131
`6,314,192 B1
`6,324,573 B1
`6,324,650 B1
`6,330,335 B1
`6,343,138 B1
`6,343,738 B1
`6,389,293 B1
`6,526,380 B1
`5,542,502 B1
`6,633,846 B1
`6,647,096 B1
`6,665,644 B1
`6,671,292 B1
`6,728,682 B2
`6,760,697 B1
`6,763,099 B1
`6,880,171 131
`6,895,086 B2
`6,907,387 B1
`7,039,585 B2
`7,050,918 B2
`7,079,637 B1
`7,103,549 B2
`7,106,843 B1
`7,123,704 B2
`7,133,828 B2
`7,149,788 B1
`7,248,585 B2
`7,256,816 B2
`7,277,468 132
`7,417,983 B2
`7,519,169 B1
`7,529,357 131
`7,596,498 B2
`7,639,791 B2
`7,554,243 B2
`7,826,604 B2
`7,961,860 B1
`8,630,726 B2
`2001/0056461 A1
`2002/0002464 A1
`2002/0010587 A1
`2002/0032566 A1
`2003/0023444 A1
`2003/0040326 A1
`2004/0252184 A1
`2005/0010411 A1
`2005/0080625 A1
`2005/0114192 A1
`2005/0128283 A1
`2005/0144004 A1
`2005/0182628 A1
`2006/0064037 A1
`2006/0087554 A1
`2006/0087555 A1
`2006/0200353 A1
`2006/0285650 A1
`2007/0071206 A1
`2007/0185717 A1
`2007/0237099 A1
`2007/0244690 A1
`2008/0000966 A1
`
`10/2000 Hall et al.
`10/2000 Johnson
`2/2001 Rudokas et :11.
`2/2001 Ginter et :11.
`3/2001 Moskowitz
`5/2001 C1_1eI1 61 511,
`5/2001 Glnter et a1.
`6/2001 Zhao et :11.
`6/2001 Witteman
`6/2001 Glnter et a1.
`7/2001 Ahmadetal,
`7/2001 Rhoads
`8/2001 Bowater et :11.
`8/2001 Rhoads
`9/2001 R110_adS
`10/2001 Boc1onek et :11.
`11/2001 Bancroft
`11/2001 Chenet :11.
`11/2001 Rh<_>a¢1S
`11/2001 Og11V1e
`12/2001 Rhoads
`1/2002 Rhoaols
`2/2002 Ogllvle
`5/2002 Clore
`2/2003 Thelen et :11.
`4/2003 E13231
`10/2003 Bennett et :11.
`11/2003 \/Iilliorn et :11.
`12/2003 Kanevsky et :11.
`12/2003 HaaI_tsen
`4/2004 Fasc1ano
`7/2004 Voumeyeretal.
`7/2004 B11nk
`4/2005 Ahmade1a1~
`5/2005 Vlartin
`6/2005 Reardon
`5/2006 Wilmot et :11.
`5/2006 Pupalaikis et :11.
`7/2006 V1cNittet :11.
`9/2006 Bennett et :11.
`9/2006 Gainsboro et :11.
`10/2005 \/11111111
`11/2006 Scarano et a1.
`12/2006 Gundla et a1.
`7/2007 V1a1”tlI1
`8/2007 Profanchik et :11.
`10/2007 Tian 6131,
`8/2008 He etal.
`4/2009 Hingoranee et :11.
`5/2009 Rae 6131,
`9/2009 Basu etal.
`12/2009 Hodge
`2/2010 Ma1”t1I1
`11/2010 MaIt1n
`6/2011 McFar1en
`1/2014 Hodge et a1,
`12/2001 Kampe et a1.
`1/2002 Petrushin
`1/2002 Peltrushin
`3/2002 Tzirkel-Hancock et :11.
`1/2003 St. John
`2/2003 Levy et :11.
`12/2004 Hesse et :11.
`1/2005 Rigazio et :11.
`4/2005 Bennett et :11.
`5/2005 Tor et :11.
`6/2005 Bulriss et :11.
`6/2005 Bennett et :11.
`8/2005 Choi
`3/2006 Shalon et al.
`4/2006 Boyd et 211.
`4/2006 Boyd et 211.
`9/2006 Bennett
`12/2006 Hodge
`3/2007 Gainsboro et 211.
`8/2007 Bennett
`10/2007 He et 211.
`10/2007 Peters
`1/2008 Keiser
`
`Page 2
`
`

`
`processing and new conferencing technology), Frankel, Elana,
`Teleconnect, v.14 n.5, p. 131(3), May 1996.
`Coherent Announces Industry’s First Remote Management System
`for Echo Cancellers, Business Wire, Mar. 3, 1997.
`Inmate Telephone Services: Large Business: Voice, Oct. 2, 2001.
`National Alliance of Gang Investigators Associations, 2005 National
`Gang Threat Assessment, 2005, pp. vi and 5-7, Bureau of Justice
`Assistance, Office of Justice Programs, U.S. Department of Justice.
`National Major Gang Task Force, A Study of Gangs and Security
`Threat Groups in America’s Adult Prisons and Jails, 2002, United
`States.
`Newton’s Telecom Dictionary, 18th Edition, Feb. 2002, p. 168, sec-
`tion “coding theory”.
`Office of the Inspector General, Department of Justice, Criminal
`Calls: A Review of the Bureau of Prisons’ Management of Inmate
`Telephone Privileges, Chapter 4, 1999, United States.
`Statement for the Record of John S. Pistole, Assistant Director,
`Counterterrorism Division, Federal Bureau of Investigation, Before
`the Senate Judiciary Conimittee, Subcommittee on Terrorism, Tech-
`nology, and Homeland Security, Oct. 14, 2003.
`International Search Report for International Application No. PCT/
`US04/025029, European Patent Office, Netherlands, mailed on Mar.
`14, 2006.
`Supplementary European Search Report for EP Application No. EP
`04 80 9530, Munich, Germany, completed on Mar. 25, 2009.
`Office Action mailed Dec. 1, 2011, in Canadian Patent Application
`\Io. 2,534,767, DSI-ITI, LLC, filed Aug. 4, 2004.
`Final Office Action, mailed Jun.
`1, 2011,
`in U.S. Appl.
`11/819,834, filed Jun. 29, 2007.
`\Ion-Final Office Action, mailed Sep. 22, 2010, in U.S. Appl. \Io.
`11/819,834, filed Jun. 29, 2007.
`Final Office Action, mailed Nov. 28, 2011,
`12/032,200, filed Feb. 15, 2008.
`\Ion-Final Office Action, mailed May 3, 2011, in U.S. Appl. \Io.
`12/032,200, filed Feb. 15, 2008.
`Amendment and Response Under 37 C.F.R. 1.111. dated Sep. 30,
`2011, in U.S. Appl. No. 11/706,431.
`\Ion-Office action, mailed Mar. 30, 2011,
`11/706,431, filed Feb. 15, 2007.
`Final Office Action, mailed Oct. 17, 2011,
`11/706,431, filed Feb. 15, 2007.
`\Iotice of Allowance mailed Sep. 9, 2013,
`12/378,244, filed Feb. 12, 2009; 10 pages.
`\Ion-Final Office Action mailed Oct. 31, 2012, in U.S. Appl. \Io.
`12/378,244, filed Feb. 12, 2009; 12 pages.
`Final Office Action mailed Mar. 8, 2013,
`12/378,244, filed Feb. 12, 2009; 13 pages.
`
`\Io.
`
`in U.S. Appl.
`
`\Io.
`
`US 9,225,838 B2
`Page 3
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2008/0021708 A1
`2008/0106370 A1
`2008/0118045 A1
`2008/0198978 A1
`2008/0201143 A1
`2008/0201158 A1
`2008/0260133 A1
`2008/0300878 A1
`2010/0177881 A1
`
`1/2008 Bennett et al.
`5/2008 Perez et al.
`5/2008 Polozola et al.
`8/2008 Olligschlaeger
`8/2008 Olligschlaeger et al.
`8/2008 Johnson et al.
`10/2008 Hodge et al.
`12/2008 Bennett
`7/2010 Hodge
`
`FOREIGN PATENT DOCUMENTS
`
`JP
`JP
`JP
`WO
`
`60010821 A
`61135239 A
`3065826 A
`PCT/US95/14230
`
`1/1985
`6/1986
`3/1991
`11/1995
`
`OTHER PUBLICATIONS
`
`Boney, L., et al., “Digital Watermarks for Audio Signals” Proceed-
`ings of the International Conference on Multimedia Computing Sys-
`tems, p. 473-480, IEEE Computer Society Press, United States
`(1996).
`Boney, L., et al., “Digital Watermarks for Audio Signals” Proceed-
`ings of EUSIPCO-96, Eighth European Signal processing Confer-
`ence, Trieste, Italy, 10-13 (1996).
`Cox, I. J., et al.; “Secure Spread Spectrum Watermarking for Multi-
`media,” NEC Research Institute, Technical Report 95-10 (1995).
`Christel, M. G., et al., “Interactive Maps for a Digital Video Library”,
`IEEE Special Edition on Multimedia Computing, pp. 60-67, IEEE,
`United States (2000).
`Lane, I. R., et al., “Language Model Switching Based on Topic
`Detection for Dialog Speech Recognition,” Proceedings ofthe IEEE-
`ICASSP, vol. 1, pp. 616-619, IEEE, United States (2003).
`Olligschlaeger, A. M., Criminal Intelligence Databases and Applica-
`tions, in Marilyn B. Peterson, Bob Morehouse, and Richard Wright,
`Intelligence 2000: Revising the Basic Elements—A Guide for Intel-
`ligence Professionals, 2000, ajoint publication ofIALEIA and LEIU,
`United States.
`Silberg L. “Digital on Call,” HFN The Weekly Newspaper for the
`Home Furnishing Network, p. 97, Mar. 17, 1997.
`Audioconferencing options.
`(Teleconference Units, Conference
`Bridges and Sevice Bureaus) (includes related articles on speech
`
`Page 3
`
`in U.S. Appl.
`
`\Io.
`
`in U.S. Appl.
`
`\Io.
`
`in U.S. Appl.
`
`\Io.
`
`in U.S. Appl.
`
`\Io.
`
`Page 3
`
`

`
`U.S. Patent
`
`Dec. 29, 2015
`
`Sheet 1 of 7
`
`US 9,225,838 B2
`
`mcocam_m._..
`
`::
`
`%llill@
`
`émd8:8%o:.
`v_§2mz
`
`o:ocam_m._.
`
`.
`
`_..0_..._
`
`
`co_Em>E:o.__0T._93QEOO
`__mo
`
`
`
`
`
`>:_:E_ocozoflma
`
`L2_...
`
`>m>>.wmE._.:?“mo:/mm_ozw:o:c__.Eoo‘m:
`
`
`
`2:..mo.
`
`m:o;am_m._,
`
`xaémz
`
`EmE:_
`
`m:o..Em_m._..
`
`Page 4
`
`Page 4
`
`
`
`
`

`
`U.S. Patent
`
`Dec. 29, 2015
`
`Sheet 2 of7
`
`US 9,225,838 B2
`
`101
`
`\‘
`
`209
`
`211
`
`206
`
`From 113
`
`“
`
`114
`
`Intevface Porz
`
`To -115
`
`2
`
`23:‘
`
`113
`
`‘
`"
`Energy Detect
`Circuitry
`
`‘
`A/D
`Converter
`
`-.
`
`201
`
`Microprocessor
`
`Digitai Signal
`processor
`
`'
`
`205
`
`
`
`2
`
`07
`
`g
`
`FIG. 2
`
`Page 5
`
`Page 5
`
`

`
`U.S. Patent
`
`Dec. 29, 2015
`
`Sheet 3 of7
`
`US 9,225,838 B2
`
`xmmm
`
`.2o2mQ
`
`Sm
`
`33¢
`
`._mzsm._.m
`
`m.0_u_
`
`Em
`
`momo...
`
`Smo._.
`
`Page 6
`
`Page 6
`
`
`

`
`U.S. Patent
`
`Dec. 29, 2015
`
`Sheet 4 of7
`
`US 9,225,838 B2
`
`smww.2534
`
`comfiwvuofi
`
`2§S
`
`aw
`
`coumwmfioi
`
`EanmgwmmvivEam#\mEmmmmm
`
`
`
`Ksxoommmmcjv_£3._C.
`
`mmwivm>mmmmwm>E
`
`
`comm$§2S
`
`
`
`mwmozmsoscmcoo
`
`»m>>-mmE.w
`
`ceE.m>E38_Q
`
`comoflmm.
`
`
`
`._®>._.wmwmtmw..............
`
`Ev
`
`Na
`
`w;.5;
`
`_m_am
`
`m3_2»F/43
`
`Page 7
`
`
`
`.§:_&mcw:,
`
`Ezmummum
`
`_.NwEvufimwcommimwmmEEou
`
`WSE
`
`mew
`
`me?8.".\v\v\
`
`Emcmm
`
`Page 7
`
`
`
`
`
`
`

`
`U.S. Patent
`
`Dec. 29, 2015
`
`Sheet 5 of 7
`
`US 9,225,838 B2
`
`500
`
`Siart
`
`515
`
`
`
`Notify
`
`Cail
`
`'!'hree-Way
`
`
`
`
`
`
`/ E
`
`501 A
`
`
`3oniinuous:
`Monitor
`Audio Exceed
`Audio
`Maximum
`St:'ea‘:m
`
`Aiiowed? ‘
`
`
`
`SE35-mce
`Deiectecé’?
`
`503
`
`Monitor
`Audio
`Streatm
`
`No
`
`Minimum
`Threshoid
`Exceeded?
`
`‘
`
`‘
`
`
`
`
`No
`
`No
`
`Page 8
`
`Page 8
`
`

`
`U.S. Patent
`
`Dec. 29, 2015
`
`Sheet 6 of7
`
`US 9,225,838 B2
`
`600
`
`Start
`
`\\
`
`
`
`
`Notify Three-
`Way Call
`
`A
`
`5
`
`50?
`
`\\*
`
`
`
`Continuous
`Monitor
`
`Audio Exceed
`Audio
`
`Maximum
`Stream
`
`Ilowed?
`
`
`
`~ 505
`
`
`Maximum
`; Monitor
`Threshold
`Audio
`Stream
`
`
`
`603
`
`FIG. 6
`
`6m
`
`No
`
`Page9
`
`Page 9
`
`

`
`U.S. Patent
`
`Dec. 29, 2015
`
`Sheet 7 of 7
`
`US 9,225,838 B2
`
`700
`
`Stan
`
`r
`arame ers
`n gure
`CND Clrwit
`
`
`701 A
`
`_ Monitor both sides of Audio
`Stream
`
`705
`
`Test me next sample against
`silence thresholds.
`
`Yes
`
`Save as ‘Beginning of
`Noise Sample‘
`
`
`
`Test the next sample against
`
`Reset ‘Silence
`V Count’ value.
`
`
`703
`
`silence thresholds.
`
`
`
`
`lncrament ‘Silence
`717
`
`Count’ value.
`
`
`
`
`
`
`
`
`Reset ‘Beginning of
`Noise Sample
`Numbef and ‘End of
`Noise Sample
`Number.___‘_/
`
`/
`
`E
`
` equal “Min Silence’
`
`727
`
`719
`
`threshold?
`
`Yes
`+
`Save as the ‘End of Noise
`Sample‘
`
`\
`
`Page 10
`
`FIG. 7
`
`729
`
`End
`
`Ye_s
`
`Play message and disconnect call
`due lo 3way calling violation.
`
`F,_,_.
`Yes
`723
`
`
`
`
`
`Is the
`
`difference of ‘End of
`Noise Sample’ and ‘Beginning
`of Nessa Sample‘ between the
`~ in and Max Constant Nois
`Length setting?
`
`
`
`
`
`Page 10
`
`

`
`US 9,225,838 B2
`
`1
`SYSTEM AND METHOD FOR DETECTING
`THREE-WAY CALL CIRCUMVENTION
`ATTEMPTS
`
`CROSS-REFERENCE TO RELATED
`APPLICATION
`
`This is a continuation-in-part application of U.S. patent
`application Ser. No. 12/378,244, filed Feb. 12, 2009, which is
`incorporated herein by reference in its entirety.
`
`FIELD OF THE INVENTION
`
`The present invention relates generally to the field of
`detecting three-way call attempts in controlled telecommuni-
`cations systems. In particular, the present invention relates to
`a system and method for preventing a user from successfully
`circumventing or masking a three-way call attempt by gen-
`erating a continuous or constant noise. The system and
`method of the present invention may be utilized with any
`existing three-way call detection system or method. The
`present invention preferably monitors for periods of silence
`and whether the examined samples are below a pre-deter-
`mined threshold. Ifthe pre-determined threshold is exceeded,
`the present invention determines that an attempt to circum-
`vent a three-way call has occurred if the amount of time
`between periods of silence exceeds the maximum allowable
`duration for continuous audio. The system also includes a
`continuous noise detection algorithm for detecting the pres-
`ence of false positives in the audio steam.
`
`BACKGROUND OF THE INVENTION
`
`Many institutions, such as prisons, nursing homes, mental
`institutions, etc., include controlled telecommunications sys-
`tems that offer inmates or residents limited calling access.
`One reason for controlling use of the system is to prevent the
`institution from incurring unaccountable telephone costs.
`Other reasons for controlling access to the system include
`preventing harassing calls to outside parties, preventing
`fraudulent activities, etc. Therefore, systems in such environ-
`ments often monitor and control the telephone activity ofeach
`inmate or resident. For example, systems may restrict calling
`to only certain telephone numbers. Systems may also have a
`means ofmaintaining call records for each inmate or resident,
`and a means for communicating with called parties to enable
`the called parties to prevent future telephone calls from
`inmates or residents. In short, the communications system
`used in a regulated institution must employ unique monitor-
`ing and control functions often unnecessary in other types of
`telecommunications systems.
`In order for the methods of monitoring and control to be
`effective, it is important to prevent inmates or residents from
`exploiting any loopholes that can be used to bypass the con-
`trol features of the system. For example, inmates or residents
`have been known to use three-way calling to have an outside
`party connect the inmate or resident to a blocked number. A
`three-way call
`is initiated when the remote called party
`depresses the hook switch on the telephone, generating a
`hook flash signal. The caller is temporarily put on hold while
`the called party establishes a connection with a third party.
`Then, all three parties can converse. Using three-way calling,
`the inmate or resident may utilize the institution’s call system
`to, among other things, access blocked telephone numbers,
`for example, to perpetrate additional criminal activities, or
`harass certain parties.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`2
`
`It is therefore critical to carefully monitor all outgoing
`telephone calls for three-way call attempts. Without such
`monitoring, many of the system’s control features of a tele-
`communications system can be rendered ineffective. Cur-
`rently, there are systems and methods known in the art for
`detecting three-way call attempts. Many of these systems
`however, are inaccurate and subject to both false positives and
`false negatives. Also, many ofthese systems are effective only
`in certain types of telecommunications systems.
`For example, one such system known in the art for detect-
`ing three-way call attempts monitors for pulses of energy
`indicative of a hook-flash by detecting the frequency of the
`energy pulse to determine if it is characteristic of a hook-flash
`(i.e., a three-way call attempt). Specifically,
`the system
`includes a low pass filter for passing energy signals having
`frequencies below 500 Hertz (“Hz”), preferably in the range
`of l 00 to 300 Hz, and an energy detector for detecting specific
`electrical energy pulses passing through the filter and having
`a predetermined minimum magnitude. The system also
`includes a software window analyzer, which cooperates with
`the energy detector to detect specific events, such as sound,
`occurring on the telephone line during a predetermined time
`window after the detection of the aforementioned energy
`pulse. The software window analyzer includes a timer means
`that is activated by the detection of the energy pulse, and a
`sound means for detecting the occurrence of sound on the
`telephone line during at least one ofmultiple windows oftime
`defined by the timer means. The non-occurrence of sound on
`the telephone line during a specified time window is used by
`the system to confirm that the detected energy pulse is in fact
`a three-way call attempt. A counter means is further imple-
`mented for counting specific energy pulses detected by the
`energy detector during the time window when the remote
`party is using a pulse-dial telephone. This system, by simply
`monitoring for a pulse composed of certain frequencies, is
`often inaccurate and cannot operate in digital systems.
`A similar system is also designed to detect the presence of
`an energy pulse indicative of a hook-flash. Specifically, the
`system is designed to detect a pulse that is comprised of
`frequency components below 500 Hz and above a predeter-
`mined threshold. The existence ofthe hook-flash is confirmed
`
`by digital signal processing equipment which identifies a
`rapid drop-off in energy, which is indicative of a hook-flash
`signal. Optionally, the hook-flash may be further confirmed
`by including software for cooperating with the energy detec-
`tor to ascertain whether sound has occurred in the telecom-
`
`munication during a predetermined period following the first
`hook-flash signal.
`Still another known system includes three-way call detec-
`tion circuit that uses digital signal processing to identify a
`third party connection. The system operates by establishing a
`baseline background noise. The system identifies a drop in
`noise level below the established baseline background noise
`as an indication that a three-way conference call has been
`attempted by the called and/or calling party.
`Yet another known system monitors all connected tele-
`phone lines for indicia representative of a three-way call
`attempt. For example, the system may monitor for a digital
`PCM signal or a period of silence, followed by a release pulse,
`followed by yet another period of silence. Upon detection of
`a possible three-way call attempt, the three-way call detection
`circuit examines the digital signals to determine the spectral
`characteristics (i.e., time duration, frequency, and energy
`level) of a suspected release pulse of the suspected three-way
`call attempt. The system utilizes pattern recognition tech-
`niques to compare the suspected release pulse with a refer-
`ence release pulse indicative of a three-way call attempt. The
`
`Page 1 1
`
`Page 11
`
`

`
`US 9,225,838 B2
`
`3
`system also monitors for periods of silence before and after
`the suspected release pulse. If the system finds that the sus-
`pected release pulse is substantially similar to the reference
`release pulse and that the correct periods of silence surround-
`ing the suspected release pulse are present,
`the system
`responds to the detection, for example, by disconnecting the
`telephone call, playing a recording, or creating a record of the
`three-way call attempt.
`Yet another known system for detecting three-way calls
`monitors audio signals for features that distinguish voice and
`line-generated audio signals from audio signals produced by
`events associated with three-way call attempts. The distin-
`guishing features used are pulse patterns that are strongly
`correlated with either audio signals generated by central
`office switching activity (‘clicks’) (reference features) or
`voice-generated audio signals (reset features). Audio signals
`are continuously monitored for reference and reset features
`over selected intervals or sampling windows. Sampling win-
`dows are reset whenever reset features are detected in the
`
`associated audio signal segment. Audio signals that are free of
`reset features and include reference features are tagged as
`potential click events. A three-way call event is declared when
`audio signals associated with consecutive sample windows
`are tagged as potential three-way call events. In this system, a
`control program samples the audio signal at the selected rate
`and sorts the sampled signals during a sampling window to
`produce a profile of the sampled audio signal. The profile
`comprises counters for tracking the number, strength (loud-
`ness), and separation of signal pulses. These counters may be
`compared in various combinations with counter values
`extracted from voice-generated audio signals (reset thresh-
`olds) and three-way call generated audio signals (reference
`thresholds) to declare a three-way call attempt, continue sam-
`pling, or reset the sampling window.
`Another known system counts signal characteristics to
`detect three-way call attempts. The system samples audio
`from a telephone conversation, sorts the sampled signals into
`a profile of levels for the sampled audio signals, and monitors
`the profile of sampled audio signals for reset and reference
`conditions. In this system, a reset condition is a pulse pattern
`inconsistent with patterns generated by three-way call events.
`Reference conditions, in contrast, are pulse patterns identified
`from sampled audio signals that are consistent with patterns
`generated by three-way call events. If a reference condition is
`detected, the telephone call is tagged as having a possible
`three-way call attempt. The system concludes that a three-
`way call attempt has occurred when two consecutive tags
`have been made to the same telephone call.
`Still another known system detects three-way calls by rec-
`ognizing that each telephone connection has a characteristic
`reflection, or echo, idiosyncratic to that connection. The echo
`characteristics of a particular telephone connection are
`altered, for example, when a three-way calling feature is
`activated by the remote party at the original destination
`thereby adding a third party at a secondary destination. The
`system includes means for “zeroing out” or canceling the
`characteristic echo once a connection has been established by
`using an adaptive finite impulse response (FIR) filter. The
`system also includes response means for implementing a
`predetermined response when an undesirable event
`is
`detected. Examples of the responses which can be pre-pro-
`grammed include call termination, playing a prerecorded
`message, generating a tone which may be heard by one or
`more parties to the call, muting the microphone of the local
`telephone and recording the date and time of the remote
`party’s attempt to initiate the three-way call.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4
`
`Other systems are known which incorporate methods of
`monitoring calls in telecommunications management sys-
`tems. For example, the methods include means for detecting
`tones commonly associated with call bridging and call for-
`warding attempts. One such method is directed to the detec-
`tion of tones such as ring signals, busy signals, special infor-
`mation tones (“SIT tones”), dual tone multi-frequency tones
`(“DTMF”), call progress tones or other similar tones charac-
`teristic of the placement of a telephone call.
`Yet another known system incorporates spread spectrum
`techniques to detect three-way calls. The system measures
`delay times associated with multiple echoes of a reference
`signal transmitted over a two-way call. This initial echo char-
`acteristic is measured and recorded in an initial echo profile.
`Whether a three-way calling event has occurred is determined
`by virtue of changes in the delay times and number of echoes
`in each subsequent echo profile when compared with the
`initial echo profile. In view of the foregoing, a need clearly
`exists for a method and system of three-way call detection
`capable of accurately detecting three-way call attempts in
`analog and digital telecommunications systems. This method
`and system may be used in conjunction with any current
`system, but is preferably implemented within a system that
`detects three-way call attempts by analyzing the communi-
`cations path between the originator and recipient in a tele-
`communications network.
`
`SUMMARY OF THE INVENTION
`
`The present invention embodies a three-way call detection
`circuit for use with an existing telephone management sys-
`tem, and is designed to reduce the number of three-way call
`attempts not detected by current three-way call detection
`techniques. The system of the present invention may be
`implemented in a variety of facilities including, but not lim-
`ited to, penal institutions, mental institutions, nursing homes,
`rehabilitation centers, correctional facilities, government
`agencies, private and public business and the like.
`Typically, a telephone management system used by such
`facilities consists of a multitude of telephones connected to a
`switchboard device. The switchboard device routes calls, per-
`forms voice prompts and responds to menu selections. Tele-
`phone calls placed by users of the telephone management
`system are routed through the switchboard device and con-
`nected to the proper outgoing trunk based on the type of call
`placed (e.g., collect, debit, etc.). An integrated cross point
`switch enables any telephone to access any available outgo-
`ing trunk.
`The three-way call detection circuit of the present inven-
`tion is utilized each time a telephone call is placed by a user of
`the telephone management system. The circuit constantly
`monitors all active trunk lines and telephone conversations.
`During a telephone call, the three-way call detection circuit
`monitors the connection for pulses of energy associated with
`the act of the called party initiating a three-way call. The
`system of the present invention monitors the presence of
`audio signals generated by the central office switching activ-
`ity (hereinafter, “clicks”) indicative of a three-way call initia-
`tion attempt.
`For a called party to initiate a three-way call, the called
`party typically depresses the hook-switch momentarily to put
`the calling party on hold and to call a third-party. The called
`party’s depression of the hook-switch generates a hook-flash
`signal, which results in the central office generating a click on
`the inmate’ s telephone line. It has been shown that in certain
`instances a user can circumvent current three-way call detec-
`tion systems by “covering up,” “masking,” or otherwise hid-
`
`Page 12
`
`Page 12
`
`

`
`US 9,225,838 B2
`
`5
`ing a three-way call attempt by creating a constant or con-
`tinuous noise (e.g., a constant hum or a constant hiss) while
`the three-way call is being attempted. Prior art systems are not
`designed to nor are they capable of detecting such a continu-
`ous noise. Thus, users of prior art systems can bypass the
`system simply creating continuous noise during a three-way
`call attempt.
`The present invention provides for a method to detect cir-
`cumvention attempts during a three-way call attempt. Spe-
`cifically, during each call, the system monitors for periods of
`silence (e.g., by examining a number of samples from an
`audio stream to determine whether the sample is below a
`certain, pre-determined threshold). When the system prefer-
`ably detects that the samples are below the pre-determined
`threshold, it continues to monitor the audio samples until the
`pre-determined threshold is exceeded. After the pre-deter-
`mined threshold is reached, the system continues to examine
`the audio stream for the next period of silence. The system
`then determines the amount of time between the periods of
`silence to determine whether it exceeds the maximum allow-
`
`able duration for continuous audio. If the elapsed time is
`greater than a pre-determined maximum duration, the system
`determines that an attempt to circumvent the three-way call
`system has occurred and appropriate action is taken.
`As a further check to avoid potential false positives, the
`present invention provides a system and method to monitor
`signal power of the samples during the period when the pre-
`determined threshold is exceeded. A false positive occurs
`when the signal power is not evenly distributed across the
`period during which the pre-determined threshold is above
`the maximum allowed.
`
`Therefore, it is an object ofthe present invention to provide
`a three-way call detection method and system for detecting
`three-way call circumvention attempts.
`It is another object of the present invention to monitor the
`signal power of the audio signal for detecting three-way call
`circumvention attempts.
`Furthermore, it is an object of the invention to accurately
`detect three-way call attempts and respond with a designated
`action (e.g., disconnect, flag, record, monitor, etc.).
`It is another object of the invention to provide a three-way
`call detection method and circuit which stores all detected
`
`three-way call attempts in a central database.
`It is still a further object of the invention to provide a
`three-way call detection method and circuit capable of moni-
`toring a telephone conversation from the called party’s side of
`the connection.
`
`Additionally, it is an object of the invention to provide a
`three-way call detection method and circuit which is compat-
`ible with pre-existing telephone management systems.
`Finally, it is a further object of the invention to provide a
`three-way call detection method and circuit compatible with
`both analog and digital telecommunications systems.
`Other objects, features, and characteristics of the present
`invention, as well as the methods of operation and functions
`of the related elements of the structure, and the combination
`of parts and economies of manufacture, will become more
`apparent upon c