(19) l+I
`
`Canadian
`Intellectual Property
`Office
`
`Office de la Propriete
`lntellectuelle
`du Canada
`
`<11) CA 2 290 967
`(43) 28.01.1999
`
`(13) A1
`
`An Agency of
`Industry Canada
`
`Un organisme
`d'lndustrie Canada
`
`(51) Int. Cl.':
`
`H04L 001/22
`
`(85) 23.11.1999
`
`(86) PCT/EP98/03747
`
`87 W099/04507
`
`(72)
`
`(74)
`
`HENKEL, HANS-JURGEN (DE).
`
`Fetherstonhaugh & Co.
`
`197 28 061.7 DE 01.07 .1997
`
`DEUTSCHE TELEKOM AG,
`Friedrich-Ebert-Allee 140
`D-53113, BONN, XX (DE).
`
`(12)
`
`(21) 2 290 967
`
`(22) 19.06.1998
`
`(30)
`
`(71)
`
`(54)
`
`(54)
`
`(57)
`
`PROCEDE ET SYSTEME POUR COMMANDER L'UTILISATION DE LA CAPACITE DE TRANSMISSION DE
`SATELLITES DANS DES RESEAUX TERRESTRES
`METHOD AND SYSTEM FOR CONTROLLING THE USE OF SATELLITE TRANSMISSION CAPACITY IN
`TERRESTRIAL NETWORKS
`
`The invention relates to a circuit and a method,
`characterized
`in
`that an
`independent,
`local control
`unit (7) which monitors a back-up terminal cooperates
`to a
`limited extent with
`the data
`transmission
`apparatus of the user and from the analysis of a data
`control signal recognizes the presence of a case of
`substitution switching. Via lines (10 to 14) and modems
`(15)
`said
`control
`unit
`(7)
`switches
`on
`the
`transmission carrier (19) of the satellite modem (15)
`affected, which is connected to a satellite antenna (18)
`. The
`satellite antennae (18) are connected
`to the
`satellite (20) via
`the
`transmission carrier (19). All
`other terminals in the network which are not affected
`also
`receive
`the
`transmission carrier
`(19) of
`the
`satellite modem
`(15) concerned.
`In
`this way
`the
`transmission capacity of the asynchronous overhead of
`the satellite modem (15) is used for the transmission
`of target
`addresses. A hub (4)
`is connected to the
`terrestrial network
`(1) via an
`interface card or a
`modem
`(5), which network
`in
`turn
`is connected
`to
`routers
`(6) by means of lines (2 or 3). Customer
`installations
`(8) or
`terminals
`(9)
`are connected
`to
`the
`routers
`(6)
`by means
`of
`lines
`(10).
`
`Pet., Exh. 1008, p. 1
`
`

`
`0 PI C
`
`OFFICE DE LA PROPRIETE
`
`INTELLECTUELLE DC CANADA
`
`CI P 0
`
`02) (19) ccA) Deman de-Application
`
`CANADIAN IKTELLECTUAL
`
`PROPERTY OFFICE
`
`(21) (Al) 2,290,967
`(86) 1998/06/19
`(87) 1999/01128
`
`(72) HENKEL, HANS-JURGEN, DE
`(71) DEUTSCHE TELEKOM AG, DE
`(51) Int.Cl. 7 H04L 1/22
`(30) 1997/07/01 (197 28 061.7) DE
`(54) PROCEDE ET SYSTEME POUR COl\fMANDER
`L'UTILISATION DE LA CAPACITE DE TRANSMISSION DE
`SATELLITES DANS DES RESEAUX TERRESTRES
`(54) METHOD AND SYSTEM FOR CONTROLLING THE USE OF
`SATELLITE TRANSMISSION CAPACITY IN TERRESTRIAL
`NETWORKS
`
`....!!'..
`
`13
`
`-~~
`L--11~
`i
`I
`
`lllhl
`!""~'
`-·-·-·--·-·-·-·-·-! -~i-·-·-·-·-·-·-·
`
`........................ ..
`
`•
`
`10
`
`(57) L 'invention eoncerne un eireuit et un procede
`caracterises en ce qu'une unite de commande locale
`independante
`(7), qui
`contriile un
`terminal de
`sauvegardc, coopcre de fa9on limit6e avce le dispositif
`de transmission de donnees de l 'utilisateur et detecte la
`presence d \m cas de commutation sur secours. ii paiiir
`de !'analyse d'un signal de commande de donnees. Cette
`par I 'intermediaire de
`unite de commande (7)
`ii 14) cl de modems (15), la porlcusc
`lignes (I 0
`d'emission (19) du modem de satellite (15) eonc.::m~ qui
`est raccorde a une antenne de satellite (18). Les antennes
`(20) par
`de
`satellite
`sont
`reliees
`au
`satellite
`
`(57) The invention relates to a circuit and a method,
`characterized in that an independent, local control unit
`(7) which monitors a hack-up terminal cooperates to a
`limited extent with the data transmission apparatus of lhc
`user and from the
`of a data control
`recognizes the presence of a case of substitution
`switching. Via lines (10 to 14) and modems (15) said
`control unit (7) switches on the transmission cam er (I 9)
`of the satcllilc modem ( 15) affected, which is connceted
`to a satellite antenna (18). The satellite antennae (18) me
`connected to the satellite (20) via the transmission caiTier
`(19) All other tem1inals in the network which are not
`
`••• lndustrie Canada
`
`Industry Canada
`
`Pet., Exh. 1008, p. 2
`
`

`
`0 PI C
`
`OFFICE DE LA PROPRIETE
`
`INTELLECTUELLE DC CANADA
`
`CI P 0
`
`CANADIAN IKTELLECTUAL
`
`PROPERTY OFFICE
`
`(21) (Al) 2,290,967
`(86) 1998/06/19
`(87) 1999/01128
`
`l'intem1ediaire de la porteuse d'emission (19). Tousles
`autres tenninaux non concemes dans le reseau re901vent
`la pmteuse d'emission (19) du modem de satellite
`concerne ( 15). La capacite de transmission du surdehit
`asynclmme du modem de satellite (15) est utilisee pour
`la transmission d'adresses cihles. Un concentrateur (4)
`est raccorde par I' intermedialre d 'une caiie mterface ou
`d\m modem (5) a \111 reseau terrestre (1) lui-meme
`raccorde ii des routeurs (6) par 1 'intermediaire de lignes
`(2 ou 3). Les installations client (8) ou Jes lern1inaux (9)
`sont raccordes aux routeurs (6) par l'intermediaire de
`lignes (10) .
`
`affected also receive the transmission carrier (19) of the
`In
`this way
`the
`satellite modem (15) concerned.
`transmission capacity of the asynchronous overhead of
`the satellite modem ( 15) is used for the transmission of
`target addresses. A huh ( 4) is connected to the terrestrial
`network (1) via an interface card or a modem (5), which
`network 111 turn is com1ected to routers ( 6) by means of
`lines (2 or 3) Customer installations (8) or terminals (9)
`are connected to the routers (6) hy means of lines (10).
`
`••• lndustrie Canada
`
`Industry Canada
`
`Pet., Exh. 1008, p. 3
`
`

`
`CA 02290967 1999-11-23
`
`PCT
`-
`WELTORGANISATION FOR OEISTIOES EIGENTUM
`-
`Intemationales Bilro
`INTERNATIONALE ANMELDUNG VEROFFEN'ILICIIT NACH DEM VERTRAG OBER DIE
`INTERNATIONALE ZUSAMMENARBEIT AUF DEM GEBIBT DES PATENTWESENS (PCT)
`(11) Internationale Veroffentlichwtgsnumrner: WO 99/04507
`
`A3
`
`(43) Internationales
`Veroffentllchungsdatuni:
`
`28. Januar 1999 (28.01.99)
`
`(51) Internationale Patentklassillkation 6 :
`H04L 1/22
`
`(21) Internationales Aktenzeichen:
`
`PCT/EP98/03747
`
`(22) Internationales Anmeldedatum:
`
`19. Juni 1998 (19.06.98)
`
`(81} Besthnmungsstaaten: CA, CZ, HU, ID, JP, KR, PL, US,
`europaisches Patent (AT, BE, CH, CY, DE, DK, ES, FI,
`FR, GB, GR, IE, IT, LU, MC, NL, PT, SE).
`
`(30) Prloritlitsdaten:
`197 28 061.7
`
`1. Juli 1997 (01.07.97)
`
`DE
`
`Bestimmungsslaaten
`alle
`(fiir
`(71) Anmelder
`US):
`DElITSCHE TELEKOM AG
`Friedrich-Ebert-Allee 140, D-53113 Bonn (DE).
`
`ausser
`[DE/DE];
`
`(72) Erfinder; und
`(7S) Erftnder/Anmelder (nur ftlr US): HENKEL, Hans-Jtlrgen
`[DB'DE]; Robert-Koch-Strasse 5c, D-64380 RoBdorf (DE).
`
`Verliffentlkht
`Mil internationalem Recherchenbericht.
`Vor Ablauf der fur 1i'nderungen der Anspruche zuge/assenen
`Frist. Veroffentlichung wird wiederho/t falls Andenmgen
`eintreffen.
`
`(88) Veroffentlichungsdatum des internationalen Recherchenbe-
`richts:
`27. Mai 1999 (27 .05.99)
`
`(54) Title: METHOD AND SYSTEM FOR CONTROLLING Tiffi USE OF SATELLITE TRANSMISSION CAPACITY IN TERRES(cid:173)
`TRIAL NETWORKS
`
`SYSTEM
`UND
`(54) Bezeichnung: VERFAHREN
`DER
`STEUERUNG
`ZUR
`LlTEN-fJBERTRAGUNGSKAPAZITAT IN TERRESTRISCHEN NETZEN
`
`NUTZUNG
`
`VON
`
`SATEL-
`
`(57) Abstract
`
`The invention relates to a circuit and a method, characterized in
`that an independent, local control unit (7) which monitors a back-up
`tenninal cooperates to a limited extent with the data transmission
`apparatus of the user and from the analysis of a data control signal
`recognizes the presence of a case of substitution switching. Via lines
`( 10 to 14) and modems (15) said control unit (7) switches on the
`transmission canier (19) of the satellite modem ( 15) affected, which
`is connected to a satellite antenna (18). The satellite antennae (18)
`are connected to the satellite (20) via the transmission carrier (19).
`All other tenninals in the network which are not affected also receive
`the transmission carrier (19) of the satellite modem (15) concerned.
`In this way the transmission capacity of the asynchronous overhead
`of the satellite modem (15) is used for the transmission of target
`addresses. A hub (4) is connected to the terrestrial network (1) via
`an interface card or a modem (5), which network in tum is connected
`to routers (6) by means of lines (2 or 3). Customer installations (8)
`or tenninals (9) are connected to the rooters (6) by means of lines
`(10).
`
`.T.
`t-"-l
`i
`I
`
`~-=-·-·-·--·-·-·-·-·-I f~I __ ,_~ ___ :::·.·::·· ............. .
`
`.1__:_'-.....:5
`
`,()
`
`Pet., Exh. 1008, p. 4
`
`

`
`.. PCT/EP98/03747
`P96192WO. IP
`
`CA 02290967 1999-11-23
`
`FILE, P+N4N THIS AMENDED
`JE..X.T TRANSLATION
`
`DESCRIPTION
`
`PROCESS AND SYSTEM FOR CONTROLLING TIIB USE OF SATELLITE
`TRANSMlSSION CAPACITY IN TERRESTRIAL NETWORKS
`
`The invention relates to a process and circuit arrangement for controlling the use of
`
`satellite transmission capacity for the substitution of out-of-order data lines in
`
`terrestrial networks according to the preambles of claim I and claim 7, respectively.
`
`Switched trunk groups in voice and data networks are generally operated two-way
`
`alternately between computer-controlled exchanges. With this mode of operation, both
`exchanges are able, independently of each other, to access and occupy unoccupied
`
`trunks of the group. If certain data lines go down completely, this also permits
`
`automatic alternative routing to an unoccupied and operable data line of a terrestrial
`
`network.
`
`The known traffic management processes are summarized and outlined in CCITT
`
`Recommendation E412: ''Network Management Controls" (10/92). However, it is
`also known to remedy out-of-order data lines in terrestrial networks by using spare
`
`satellite transmission capacity. Particularly with regard to the access lines, alternative
`
`routing via satellite requires a manual initiation after a transmission capacity request
`has been sent to a central station. Used foe this purpose is a backward channel which is
`
`carried via terrestrial lines or via satellite.
`
`'Fhe mauua:l ll'l1ttation ofaltc111ative roadng a:ce01ding to dre prior11"f"t! tim~!/'t.
`<II'~ .. ···,,,.,....
`It may be necessary for call configurations to be transmi~.t:Q..t>he1'ocations involved
`~'"'"''"'"""'""',..,..
`and a backward channel must be relia,gly . ..avaitable in the case of an alternative routing
`request. This may - parti.cularlyin the case of a terrestrial backward channel, for
`example if cRW'ard channel and user information channel are carried in one access
`
`'".,,.,,.~
`
`.. ""',....:#'
`
`~:J!J~:i..p.t:l;M:>jem&r-beellltttlei..ae.·e~artf-ehannel-·i~.
`
`Translation P96192wo_Ea.DOC
`
`Pet., Exh. 1008, p. 5
`
`

`
`CA 02290967 1999-11-23
`
`PCT/EP98/03747
`P96192WO.IP
`
`20July1999
`
`- 2, 2a, 3-
`
`The manual initiation of alternative routing according to the prior art is time-intensive.
`
`It may be necessary for call configurations to be transmitted to the locations involved
`
`and a backward channel must be reliably available in the case of an alternative routing
`
`request. This may - particularly in the case of a terrestrial backward channel, for
`
`example if backward channel and user information channel are carried in one access
`
`line - lead to problems, because no backward channel is directly available.
`
`Described in DE 43 08 161 Al is a system for telecommunication via satellite which
`
`comprises at least one transmitting station and at least one receiving station, at least
`one monitoring circuit for monitoring the signal transmitted via the satellite link by a
`transmitting station and received by a receiving station. In the case of a fault in this
`
`signal, there is alternative routing in that at least one network module is provided, said
`
`network module automatically establishing a telecommunications call connection
`
`between a transmitting station and a receiving station via a switched network if, for
`
`example owing to weather conditions, a parameter of the signal assumes critical values
`
`and said network module again clearing down said call connection if the parameter of
`
`the signal assumes non-critical values. Consequently, said system is clearly restricted to
`monitoring the transmission quality in satellite systems with the possibility of
`
`automatically switching to fixed networks if quality defects are detected in the signal.
`
`Furthermore, described in the Patent Abstract of Japan, publication number 01293020,
`
`is a process for substituting defective satellite transmission channels by lines of fixed
`
`networks. Just like the above-described process, this process, too, cannot be employed
`
`for the event that lines of a fixed network go down and, instead, spare transmission
`
`capacity of satellite systems is used.
`
`The object of the invention is to create a process and system/circuit arrangement which
`automatically initiate and monitor alternative routing via satellite irrespective
`
`AMENDED SHEET
`
`Translation P96 l 92wo Eb.DOC
`
`Pet., Exh. 1008, p. 6
`
`

`
`CA 02290967 1999-11-23
`
`PCT /EP98/03 74 7
`P96192W0.1P
`
`20 July 1999
`
`of the transmission medium that might be out·of-order, with the satellite transmission
`
`capacity available for alternative routing purposes being usable by a large number of
`
`users and assignment in the case of alternative routing being automatic.
`
`The object of the invention is achieved by a process described in the characterizing part
`
`of claim 1.
`
`The object of the invention with regard to a system/circuit arrangement is achieved as
`
`described in the characterizing part of claim 7.
`
`Further features and embodiments of the invention are contained, with regard to the
`
`process, in the characterizing parts of claims 2 to 6 and, with regard to the
`
`system/circuit arrangement, in the characterizing parts of claims 8 to 14.
`
`The advantages of such a solution lie in the fact that a large number of satellite
`
`terminals is able, in the case of alternative routing, to access a small number of satellite
`
`transmission channels by means of an automatic, decentralized, local and intelligent
`
`control unit. The therefor necessary control software is stored in the respective local
`
`control unit. It controls and monitors the components of the terminal in the waiting
`state and in the case of alternative routing. It also takes over the automatic control of
`
`call setup and cleardown. In this case, the software reacts to control signals of the
`
`customer data device without, however, influencing the customer data itself The
`
`automatic and decentralized control of the use of satellite transmission capacity for the
`
`substitution of out·of-order lines in terrestrial networks and the alternative routing via
`
`a second transmission medium, namely satellite transmission, including automatic
`
`monitoring of capacity use, are effected via software controL the occupancy state of
`
`the satellite transmission capacity being monitored locally and the failure of the
`
`terrestrial call connection being detected locally and the alternative routing to satellite
`
`transmission being carried out independently and automatically. The function of the
`hub is passive and serves for call data collection and preconfiguration of the individual
`terminals at initial installation and if there is a change in the network layout. The
`
`AMENDED SHEET
`
`Translation P96192wo_Eb.DOC
`
`Pet., Exh. 1008, p. 7
`
`

`
`CA 02290967 1999-11-23
`
`PCT /EP98/0374 7
`P96192W0.1P
`
`20 July 1999
`
`updating of the network software can be transmitted to the terminal locations without
`
`direct involvement of personnel. Further features, such as the reserving of spare
`
`satellite capacity, are readily possible. The connection of the hub to the terminals may
`
`be accomplished in various ways, such as via a telephone-modem link, via an ISDN
`
`connection, via a GSM connection with modem, via a satellite connection within the
`
`capacity available in the network, etc. The synchronization of all satellite terminals can
`be accomplished by the integration of a ... .JfJH r gf ,.,
`
`i:d*'9itiltitfl!j
`
`AMENDED SHEET
`
`Translation P96192wo_Eb.DOC
`
`Pet., Exh. 1008, p. 8
`
`

`
`CA 02290967 1999-11-23
`
`PCT/EP98/03747
`' P96192W0.1P
`
`-mmimds at initilli i:rtstellatio0 aod if :thetc is a '1h&ge in tl:i.~
`updating of the network software can be transmitted to the termina!Jswattons without
`direct involvement of personnel. Further features, such~~g of spare
`~
`satellite capacity, are readily possible. Th
`ection of the hub to the terminals may
`
`, such as via a telephone-modem link, via an ISDN
`
`that the standard time is used as the system time for clocking.
`
`The above-described measures, process steps and system permit for the first time an
`
`independent, local control which monitors the backup terminal with the software
`
`specially written for this application, cooperates in limited manner with the data
`
`transmission device of the user and, from the analysis of a data control signal, detects
`
`the need for alternative routing. The control apparatus or the system switches on the
`
`transmission carrier of the affected satellite modem which is then received by all other,
`
`non-affected terminals in the network. The transmission capacity of the asynchronous
`
`overhead of the satellite modem is used for the transmission of destination addresses.
`
`The independent and decentralized control or administration of the satellite
`
`transmission channels of a pool by many satellite tenninals without participation of a
`
`controlling central station means that, also when the terrestrial transmission path is out
`
`of order, there is the possibility of free-running alternative routing via a different
`
`medium.
`
`Further features and embodiments of the process and circuit arrangement or system
`
`according to the invention will emerge from the below-described example
`
`embodiments.
`
`Hereinbelow, the invention is described in detail with reference to example
`
`embodiments represented in the drawings, the terms used in the appended lists of
`
`definitions and reference characters being used in the description, in the claims, in the
`
`abstract and in the description,
`
`Translation P96 l 92wo _Ea.DOC
`
`Pet., Exh. 1008, p. 9
`
`

`
`CA 02290967 1999-11-23
`
`PCT/EP98/03747
`P96192W0.1P
`
`Fig. I
`
`shows a basic diagram of a system for the substitution of out-of-order lines
`
`of a terrestrial network by alternative routing through a satellite
`
`connection~
`
`Fig. 2
`
`shows a carrier pool; and
`
`Fig. JA+B show basic flow charts for the process.
`
`Fig. 1 shows a basic circuit diagram required for the realization of the system and
`process for the automatic, decentralized control of the use of satellite transmission
`
`capacity for the substitution of out-of-order data lines in terrestrial networks. Fig. 1
`
`shows a terrestrial network 1 which is connected via each of lines 2 and 3 to a router
`
`or similar circuit 6. In the example shown, it is assumed that the line 2 is out of order.
`
`The terrestrial network 1 is also connected to a so-called hub 4 via a modem 5. The
`
`routers 6 are each connected to customer devices 8 and to terminals 9 for data input
`
`and output. In addition, the routers 6 are each connected to a stored-program
`
`controller 7, in each case via a line 12. Furthennore, each of the two stored-program
`
`controllers 7 is connected to a modem 5 via which the stored-program controllers 7
`
`are able to enter into communication via a line 11 with the hub 4, for example for the
`
`reporting of detected device errors in the free-line state. The stored-program
`controllers 7 are each connected via a line 13 to a satellite modem 15. Furthennore,
`
`there are connections via control lines 14 and 17. The two modems 15 are each in
`
`communication with a satellite antenna 18, which satellite antennas 18 are in
`
`communication with each other via a satellite 20 via certain carrier frequencies fn 19.
`A backup terminal 16 or 16' consists of:
`
`the satellite external unit, antenna 18, carrier 19 and satellite 20
`the connection to the internal unit and
`
`the internal unit with:
`
`satellite modem (sat modem) 15 and
`control device 7 = stored-program controller
`
`Translation P96 l 92wo _Ea.DOC
`
`Pet., Exh. 1008, p. 10
`
`

`
`CA 02290967 1999-11-23
`
`PCTIEP98/03747
`P96192W0.1P
`
`connection of the stored-program controller 7 to the terrestrial switched network
`
`1 via modem 5 and line 11.
`
`The hub 4 consists of a PC which is connected via a suitable interface card to the
`
`terrestrial network 1. The PC may, where appropriate, be connected to other networks
`for the forwarding of the call data for tariffing/invoicing purposes. The PC has a
`software which is able, via the terrestrial connection 11, to communicate with the
`
`individual stored-program controllers 7 of the backup terminals 16, 16'. Hub 4 and
`
`stored-program controller 7 each have their own addressing system.
`
`The hub 4 can, if required, enter into contact with the stored-program controllers 7 of
`
`the individual terminals, for example regularly at the month's end in order to
`
`interrogate the call data file.
`
`The creation and transfer of reconfiguration data to the individual terminals is manually
`
`initiated and monitored. The hub 4 is able to register the use of a plurality of
`
`transmission channel pools; the hub 4 has knowledge of the individual transmission
`
`channels (frequencies, data rate) as well as of their assignment to the respective pools.
`
`There is no online monitoring of the use of the transmission channels. In cases of
`
`faults, the stored-program controllers 7 report the modem parameters to the hub 4 for
`
`initial fault location.
`
`Fig. 2 shows a carrier pool with a number of several satellite transmission channels f1 -
`fn+t of a defined data rate. Hereinbelow, the functions of the individual components as
`
`well as their modes of operation and the interaction between them are described.
`
`The backup network - which, strictly speaking, is not a "network" at all because
`
`interconnection between all points is not possible - consists of a pool of satellite
`
`transmission channels which will be described later with reference to Fig. 2 and which
`
`can be employed specifically for use in backup networks with prepared terminals when
`
`there is a need for alternative routing. Many terminals share a small number of satellite
`
`transmission channels. There is no central authorization check for backup call setup.
`The use of the transmission channels is on a first come, first served basis. The
`
`reserving of transmission channels or prioritization in the use of the transmission
`
`Translation P96 l 92wo _Ea.DOC
`
`Pet., Exh. 1008, p. 11
`
`

`
`CA 02290967 1999-11-23
`
`PCT/EP98/03747
`. P96192W0.1P
`
`channels is basically possible, as is the central online monitoring of the use of the pool.
`
`All calls to be alternatively routed are symmetrical duplex channels (identical data rate
`
`in the send and receive directions). The individual transmission channels are combined
`into channel pairs with the mid-frequencies f..lfn+1 (n=l, 3, 5 .. ). In the original state of
`the backup network:, which is always desired, all transmission channels are unused and
`
`the transmission carriers of all approved terminals are switched off; in this case,
`approved means those terminals which have been registered for the lawful use of the
`
`transmission channels. At all terminals, the sat modems are set to receive the first
`
`transmission channel (f1); furthermore, it is assumed that all the sat modems used can
`be switched to a so-called loop back mode. Thus, an unauthorized data output can be
`
`prevented when synchronizing to any carrier 19 if the addresses are not identical. Since
`
`no terminal transmits, all sat modems 15 are in the syncloss state (synchronization loss
`
`= no reception and therefore no synchronization to a reception signal), which is
`communicated to the stored-program controller 7 via an interface and line 17. The
`stored-program controller 7 monitors the sat modem status and an output of a router 6
`
`or of the data terminal, such as terminal 9, which signals a failure detection of the
`terrestrial data line 2. A terrestrial line failure (backup case) is normally detected at
`
`both points of a call and is communicated by the respective router 6 to the stored(cid:173)
`
`program controller 7 in such a form that the DTRA signal in the data stream from the
`router 6 is evaluated (potential change). In order to prevent a protracted search
`
`process and therefore in order to accelerate alternative routing, in each point-to-point
`
`call one terminal is given a priority position as master 16 vis-a-vis the other terminal as
`
`slave 16'; only the master 16 is enabled under software control to initiate alternative
`routing.
`
`Once at the location, for example of the terminals 16, 16', the routers 6 determine the
`failure of the terrestrial line 2 ofa call, the respective stored-program controller 7
`
`detects the potential change of the DTR signal. The stored-program controller 7 of the
`
`terminal 16 switches on the transmission carrier f1 at the modem 15 (M+C interface),
`which signals the start of tariffing and changes the setting of the receiving frequency to
`f2. Via line 14, the master stored-program controller 7 transmits call information up to
`
`the establishing of the call, max. for t1=a seconds, to the terminal 16' (slave).
`
`Translation P96192wo _Ea.DOC
`
`Pet., Exh. 1008, p. 12
`
`

`
`CA 02290967 1999-11-23
`
`PCT/EP98/03 747
`P96192W0.1P
`
`The call information contains:
`
`destination address (terminal 16'),
`
`transmission frequency f2 to be set by the terminal 16',
`
`data rate,
`request to switch on the transmission carrier fz.
`
`Although normally known, frequency and data rate are transmitted for checking
`
`purposes and in order to ensure the compatibility of the modem settings. If not
`
`identical, termination of call setup for security reasons; prevention of disturbance of
`
`others by possibly impermissible carrier activation.
`
`All terminals (except terminal 16) receive f1 (modem sync). The call information is
`
`evaluated by all stored-program controllers 7. On the basis of the destination address,
`
`terminal 16' detects the call request which is directed to it; the stored-program
`controller 7 checks the setting data and switches on the transmission carrier f2; after
`establishing of the call, the terminal's own address and the current setting data are
`
`transmitted via lines 14 as confirmation to terminal 16. The modem terminal 16
`
`synchronizes to f1 and evaluates the transmitted data. Both stored-program controllers
`
`7 detect the existence of the backup call, cancel, where appropriate, the loop back
`
`mode of the participating modems and forward this, where appropriate, as starting
`
`signal (DTRB signal: potential change) to the respective router 7.
`
`Hereinbelow, the connection of the stored-program controller 7 to the hub 4 (optional,
`
`as extension of performance capability) is described. After the occurrence of a backup
`
`case, the stored-program controllers 7 of the affected terminals 9 attempt to report the
`
`fault to the hub 4 via the terrestrial switched line 2 or 3. Since, in the majority of cases,
`particularly in the access line area, the data line and the ISDN line are carried in one
`cable, the stored-program controller 7 of the out-of-order line section 2 will attempt in
`
`vain to reach the hub 4. The stored-program controller 7 of the non-out-of-order line
`
`section 3 reaches the hub 4. The hub 4 recognizes the message and deduces from the
`
`absence of a message from the second terminal that there is a fault, which leads to an
`indication on the hub 4 (monitoring computer). If the second message is also received,
`
`Translation P96 l 92wo _Ea.DOC
`
`Pet., Exh. 1008, p. 13
`
`

`
`CA 02290967 1999-11-23
`
`PCT/EP98/03747
`P96192WO. IP
`
`it is necessary to provide an indication capable of initiating a manual investigation of
`
`the message from the stored-program controller. In an existing call, the stored(cid:173)
`program controller 7 monitors the modem sync and, where appropriate, registers the
`cause of an unscheduled call tennination. Via the line 14 in both directions, the stored(cid:173)
`
`program controllers 7 themselves exchange monitoring data, such as their own
`addresses. The routers 6 of both tenninals detect, for example through regular polling,
`
`the return of the terrestrial line 2; the participating stored-program controllers 7
`
`ascertain this through a renewed potential change of the DTR signal. Via line 14, the
`
`master stored-program controller 7 requests the slave stored-program controller 7 to
`
`switch off the carrier f2 of the modem 15. Modem of the terminal 16 registers syncloss
`f2, which is taken over by the stored-program controller 7 via M+C interface 17. The
`stored-program controller 7 thereupon likewise switches off the carrier f1 (end of
`
`tariffing) and again sets the modem 15 to receive f1. Modem 15 of the terminal 16'
`
`registers syncloss f1 and stays receiving f1. Both modems 15 are, where appropriate,
`
`reset to loop back mode by the stored-program controller 7. After successful call
`cleardown, both stored-program controllers 7 independently inform the hub 4 of their
`
`return to the waiting state via the terrestrial switched lines 2 and 3.
`
`As already described, all non-active terminals receive the call information. All non(cid:173)
`addressed terminals are, after registration of the occupied carrier pair f1/f2 in the
`stored-program controller 7, set to receive the next carrier pair f3 or fn; with n=l, 3, 5,
`. . . . In order to be able to return to the original state within a reasonable time, after a
`waiting time oft2 = b sec. (with b for example 15 sec.), the respective stored~program
`controller 7 of each tenninal not involved in a call switches the modem 15 back to
`
`receive f1. If the carrier 19 is still occupied, i.e. if another terminal is using that carrier,
`
`the modem 15 synchronizes (modem sync). The stored-program controller 7 detects
`
`the modem sync and, in order to guarantee stable reception, after t3 = c sec. (15 sec.
`for example) switches the modem 15 back to receive f3/fn. After the waiting time
`t2 = b sec., there is a renewed check for f1. Ifthere is no reception of f1, i.e. modem
`syncloss, this is an indicator of the non-occupation of the carrier pair f1/f0 • All
`terminals/modems which cannot synchronize to f1, stay receiving ft. If, during an
`already existing alternative routing, i.e. f1/f2 (f.Jf11+1) occupied, there is a :further case of
`
`Translation P96192wo _Ea.DOC
`
`Pet., Exh. 1008, p. 14
`
`

`
`CA 02290967 1999-11-23
`
`PCT/EP98/03 74 7
`P96 l 92WO. IP
`
`a need for alternative routing, all non·active terminals are in a non·synchronized
`
`receiving situation. Tenninals n (3, for example) and n+l (4, for example) are
`
`requested to alternatively route; terminal 3 controls the call setup. All non-participating
`
`terminals are set to receive the next free carrier f,, and check, according to waiting time
`t2 = b, for the carriers f1 and fn until, in the ideal case, they stay receiving fi. the original
`state. The reaction time of the "network", i.e. the time required by a terminal after
`detection of a terrestrial line failure to provide a backup connection, is dependent on
`
`the number of carriers in the pool, on the duration of the checking and alternative
`
`routing operations of the modem to determine the availability of a carrier pair and
`
`possibly on other, as yet unidentified influences.
`
`Since all terminals are operated in non-synchronized manner, all checking and
`
`alternative routing operations are performed individually. After the existence of an
`
`active altemative routing, therefore, any further alternative routing request may be
`delayed in that, for example, terminal 16 (master) is currently checking on an occupied
`
`frequency and is therefore unable to react and terminal 16' (slave) is in some waiting
`position which, however, is left again after t2 = b sec. in order to check for the first free
`carrier. In order to set up the desired alternative routing, therefore, terminal 16 must,
`
`after the occupied frequency has been left, look for the next free carrier, stay there and,
`
`after activation of carrier fn, transmit its call request continuously for t1 =a sec. until
`terminal 16' has synchronized to f0 and detects the call request. This is then followed
`by the already described call setup. If call faults occur simultaneously on a plurality of
`
`terrestrial lines, there is the risk of multiple transmissions of various master terminals
`
`on one transmission channel (for exception see under star network). There may be
`
`collisions which prevent the reliable synchronization of the modems 15 of the
`
`respective slave terminals 16'