`
`
`Ex. PGS 1037
`
`
`
`EX. PGS 1037
`
`
`
`
`
`

`

`Ulllted States Patent [19]
`Chien
`
`US006011753A
`[11] Patent Number:
`[45] Date of Patent:
`
`6,011,753
`Jan. 4, 2000
`
`[54] CONTROL AND MONITORING OF DEVICES
`EXTERNAL TO A MARINE SEISMIC
`STREAMER
`
`[75] Inventor: Loring C. Chien, Katy, Tex.
`
`[73] Assignee: Syntron, Inc., Houston, Tex.
`
`[21] Appl' NO‘: 09/044’740
`[22]
`Filed;
`Mal; 19, 1998
`
`7
`[51] Int. Cl. ..................................................... .. G01V 1/22
`[52] US. Cl. .............................. .. 367/21; 367/76; 181/110
`[58] Field of Search ................................ .. 367/15, 16, 76,
`367/21, 79, 78, 18, 20, 80; 340/854.1; 181/110,
`112
`
`[56]
`
`References Cited
`U'S' PATENT DOCUMENTS
`
`4,967,400 10/1990 Woods .................................... .. 367/21
`5,058,080 10/1991 Siems et a1.
`367/79
`5,631,874
`5/1997 Mastin et a1. ........................... .. 367/15
`Primary Examiner—Christine Oda
`Assistant Examiner—Anthony Jolly
`Attorney, Agent, or Firm—Gunn & Associates, PC.
`[57]
`ABSTRACT
`Atechnique and a system provide control and monitoring of
`devices external to a marine seismic streamer by segmenting
`the conductor to Which the external devices are coupled. The
`module Which Connects Sections of the Seismic data telenb
`etry Cable is modi?ed to include a Switch, The switch is
`controlled by a command signal on the seismic data telem
`etry cable to segment the tWisted pair bus into a plurality of
`dedicated busses, each dedicated to a subset of the external
`devices, such as one or tWo such devices. In this Way, the
`external devices can be communicated With in parallel,
`rather than in series as in conventional systems.
`
`4,709,355 11/1987 Woods et a1. ........................... .. 367/16
`
`18 Claims, 4 Drawing Sheets
`
`10 \
`
`36
`
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`
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`
`36
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`34
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`
`36
`
`=*
`/~
`I I.
`
`:I “
`
`36 \12
`
`Ex. PGS 1037
`
`

`

`U.S. Patent
`
`Jan. 4,2000
`
`Sheet 1 of4
`
`6,011,753
`
`26
`
`Ex. PGS 1037
`
`

`

`US. Patent
`
`Jan. 4,2000
`
`Sheet 2 0f4
`
`6,011,753
`
`48
`
`EXTERNAL DEVICE
`
`48
`
`
`
`
`EXTERNAL DEVICE
`
`F[6.2(PRIORART)
`
`
`
`
`Ex. PGS 1037
`
`Ex. PGS 1037
`
`

`

`U.S. Patent
`
`Jan. 4,2000
`
`Sheet 3 of4
`
`6,011,753
`
`F 16.3
`(PRIOR ART)
`42
`
`r50
`/
`COMMAND/DATA
`REPEATER
`
`47
`
`44
`
`52
`
`\
`
`i}
`
`12 CHANNEL
`ACO
`
`g /—
`
`54
`
`MODULE
`STATUS
`
`46
`
`47
`
`M
`
`42
`
`If
`i
`l
`
`74
`
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`
`DATA
`
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`
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`
`CMD
`
`I
`
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`I
`|
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`I
`
`72
`
`‘
`FIG'4A
`(NORMAL MODE)
`
`MODULE
`STATUS
`
`68
`
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`I
`{66
`LOCAL DATA
`/
`1
`I
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`
`f
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`k
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`62/ MM
`
`v I
`
`v
`
`UART
`\70
`
`Ex. PGS 1037
`
`

`

`U.S. Patent
`
`Jan. 4, 2000
`
`Sheet 4 of4
`
`6,011,753
`
`60
`
`_]
`I
`
`DATA
`
`|
`
`I
`
`I
`72 '50
`l
`/
`M
`I
`LOCAL DATA 1
`
`MODULE /68
`STATUS
`
`MODEM
`
`UART
`
`74
`
`CMD
`
`I
`
`I
`|
`I
`
`16 CH ACQ
`
`I
`I
`
`l
`:
`
`I
`I
`I
`|
`
`44
`
`:
`i
`I
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`62/
`MODULE
`
`c
`
`I
`
`I
`I
`
`FIG. 4B
`(ENHANCED MODE)
`
`Ex. PGS 1037
`
`

`

`6,011,753
`
`1
`CONTROL AND MONITORING OF DEVICES
`EXTERNAL TO A MARINE SEISMIC
`STREAMER
`
`FIELD OF THE INVENTION
`
`The present invention relates generally to the ?eld of
`marine seismic acquisition systems and, more particularly,
`to the control and monitoring of devices associated With or
`coupled to a marine seismic streamer, including cable
`levelers, heading indicators, and acoustic echo-locating
`positioning equipment.
`
`BACKGROUND OF THE INVENTION
`
`In marine seismic exploration, a vessel toWs acoustic
`sources and one or more hydrophones arrayed in a streamer.
`Various heading sensors are also included, generally Within
`or associated With one or more cable levelers. Each of the
`devices is connected to but external to the streamer through
`a magnetic coil type coupling, Which alloWs free rotation of
`the external devices and Waterproof connections.
`The streamer, along With strength members, hydrophones,
`couplings, and other components, includes a high data rate
`conductor for carrying seismic and telemetry data. This high
`data rate conductor is generally connected in lengths of
`about 150 meters by a series of modules, Which among other
`functions ensures the amplitude and ?delity of the data. The
`streamer also includes a loW data rate communications
`conductor, referred to herein as a tWisted pair bus, for
`command and control of the various external devices. As
`used herein, the tWisted pair bus may also be referred to as
`the control conductor. Magnetic coils for communicating
`With external devices are connected directly to this bus.
`The modules previously referred to serve as repeaters and
`ampli?ers for the high data rate seismic and telemetry data
`being carried by the high data rate conductor. The tWisted
`pair bus also passes through each of the modules, but in
`knoWn systems the tWisted pair bus has no connections to
`any other components Within each module through Which it
`passes.
`This system of streamer high and loW speed data conduc
`tors has proved effective in conducting seismic surveys but
`it suffers a number of draWbacks. For example, since the
`tWisted pair bus is one long continuous conductor from the
`vessel to the end of the streamer, external devices coupled to
`the streamer must be communicated With in series. This
`signi?cantly sloWs the process of querying and commanding
`the external devices. Also, if one of the external devices
`develops a fault, such as a short circuit, then the entire
`external communications system is generally out of com
`mission and the streamer must be retrieved to isolate the
`fault, and then fault isolation can be a tedious undertaking.
`The long, relatively loW speed communications lines in
`the streamer, due to their length, limit the data bandWidth.
`Furthermore, as a signal is conducted along this communi
`cation channel, Which is often thousands of meters long,
`signal strength decreases. The length of the tWisted pair bus
`also has a direct, detrimental effect of the useful life of the
`charge of batteries in some of the external devices, because
`they must put out a high poWer signal in order to be able to
`communicate from the very end of the streamer.
`Sea Water in-leakage is also an all too common problem
`With seismic streamers as they are toWed behind a vessel.
`Minor damage to the skin around the streamer components
`may develop leaks Which permit sea Water to invade the
`streamer When it is toWed at depth. Even a minor electrical
`
`2
`ground in a portion of the tWisted pair bus Will ground the
`entire length of the bus, since the bus is one continuous
`conductor in knoWn systems. This characteristic also makes
`it very dif?cult to pinpoint the location of such a fault in the
`streamer for diagnostics and repair.
`Thus, there remains a need for a Way to isolate each of the
`external devices connected to a streamer so that each can he
`queried and commanded in parallel, and so that a fault in an
`external device can be isolated from the rest of the streamer.
`
`1O
`
`15
`
`25
`
`35
`
`45
`
`55
`
`SUMMARY OF THE INVENTION
`
`The present invention addresses these and other draW
`backs of the prior art by providing a technique and a system
`to segment the conductor to Which the external devices are
`coupled. The module Which connects sections of the seismic
`data telemetry cable is modi?ed to include a sWitch. The
`sWitch is controlled by a command signal on the seismic data
`telemetry cable and, on loss of poWer, the sWitch fails to a
`position for operation in the conventional mode. In other
`Words, on a loss of poWer, the sWitch provides a default
`position to permit continued standard operation of the sys
`tem.
`Upon a command to operate in an enhanced mode, the
`sWitch is positioned so that the external device control
`conductor is segmented into a series of dedicated busses,
`each bus dedicated to a speci?c module. A modem is
`provided in each module to serialiZe data to the external
`devices and to multiplex data into parallel (i.e., byte) form
`for communication over the module’s high speed data links
`to the vessel or other receiver.
`In this Way, all of the external devices coupled to the
`streamer can be addressed and heard in parallel, rather than
`each in turn. This system also provides the capability of
`isolating faults Within the streamer. Further, the enhanced
`capabilities can be exploited for systems With the data
`handling capability, While continuing to operate With sys
`tems of the conventional form. The present invention is
`applicable to seismic cables in general, including land
`based, ocean bottom, and streamer cables, but is preferably
`adapted for marine seismic streamers.
`These and other features of the present invention Will be
`apparent to those of skill in the art from a revieW of the
`folloWing detailed description along With the accompanying
`draWings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 depicts a sea-going Water craft toWing a marine
`seismic system.
`FIG. 2 provides additional details of a prior art seismic
`streamer.
`FIG. 3 is a simpli?ed schematic draWing of a prior art
`module Within the seismic streamer.
`FIG. 4A is a schematic draWing of an improved module
`of the present invention, operating in the conventional mode.
`FIG. 4B is a schematic draWing of an improved module
`of the present invention, operating in an enhanced mode.
`
`DETAILED DESCRIPTION OF A PREFERRED
`EMBODIMENT
`
`65
`
`The system depicted in FIG. 1 is a data acquisition and
`control system 10 designed for marine seismic operations.
`The system’s modular design provides the user With an
`integrated control and position system that can be custom
`iZed to meet the particular needs of each survey. The system
`
`Ex. PGS 1037
`
`

`

`3
`comprises a shipboard controller 14 aboard a vessel 16 and
`in-Water remote units 12.
`The in-Water remote units 12 include air gun arrays 18,
`Which may be of many Well knoWn types. Accompanying
`each gun array 18 is a set of gun acoustic units 20 and
`associated toW ?sh acoustic units 22 deployed beloW. The
`system also includes a tail buoy 24 and an associated toW
`?sh acoustic unit 26 at the end of each streamer 30, for
`example.
`The system may also include a toW buoy 28 and either a
`gun acoustics unit or a surface mount unit. The gun acoustics
`unit provides precise location of the seismic energy source
`relative to a ?xed reference point, While the surface mount
`acoustic unit is used in locations Where the use of streamer
`mounted remote units Would be impractical.
`Spaced along each streamer is a plurality of depth control
`devices 32, commonly referred to a birds. A depth control
`device 32 may also include a ?oat tube 34 attached to it.
`As used in this disclosure, each of the devices along the
`streamers Which require communication With the boat
`through the streamer are referred to collectively as external
`devices. Each of the external devices is coupled to the
`streamer by a knoWn electromagnetic coil arrangement to
`control and monitoring.
`Also spaced along each streamer is a set of modules 36.
`The modules provide coupling for high data rate transmis
`sion of seismic data and telemetry accumulated by the
`appropriate external devices. The modules also serve as
`mechanical support for relatively loW data rate conductors
`for control and monitoring of other appropriate external
`devices, although the loW data rate conductors in knoWn
`systems do not communicate With other components Within
`the modules. In the present invention, hoWever, the loW data
`rate conductors are connected through sWitches Within the
`modules 36, as shoWn and described beloW.
`FIG. 2 depicts a knoWn seismic streamer communication
`system. The vessel or boat 40 controls both the seismic
`acquisition streamer electronics and the external devices.
`Each of the external devices terminates independently into
`one or more systems for communication With the boat 40.
`Seismic data telemetry 42 has no signal connections to the
`external device system tWisted pair signal bus 44. Modules
`46 are located at intervals alone the cable for seismic
`acquisition surveys.
`One such knoWn module 46 is shoWn in great detail in
`FIG. 3. The seismic data telemetry lines 42 provide
`bi-directional communication to a command/data repeater
`50 Within the module. The module 46 also includes internal
`devices 52 and 54 for internal operation of the module.
`Particularly noteWorthy in connections to the module 46 is
`the fact that the tWisted pair bus 44 passes straight through
`the module 46 With no internal connections Within the
`module.
`As shoWn in FIGS. 2 and 3, communications coils 47 pass
`signals from the tWisted pair bus 44 to a corresponding coil
`49 that are part of an external device 48. In a conventional
`streamer cable, 20—60 modules may be positioned every 150
`meters apart, for example. The cable sections that contain
`the seismic data telemetry Wires 42 and the tWisted pair bus
`44 and coil 47 are provided With connectors (not shoWn) and
`are modular for easy maintenance.
`The communications channels on the tWisted pair bus 44
`commonly use modulation schemes such as frequency shift
`keying (FSK) in knoWn systems. Carrier frequencies are in
`the range of 27 KHZ. Alternatively, these communications
`channels may use phase shift keying (PSK) With similar
`
`10
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`6,011,753
`
`4
`frequencies and bandWidths. In knoWn systems, as shoWn in
`FIGS. 2 and 3, the bandWidth is signi?cantly limited because
`of the continuous length of the tWisted pair bus 44.
`Each external device 48 is attached to the streamer cable
`by means of a rotating collar (not shoWn) Which alloWs the
`device to sWivel around the circumference of the cable but
`keep the device internal coil 49 positioned properly relative
`to the cable internal coil 47. Thus, each external device 48
`communicates With the streamer cable by electromagnetic
`coupling betWeen the coils 47 and 49.
`As shoWn in FIGS. 4A and 4B, the present invention thus
`provides communication betWeen the tWisted pair bus 44
`and the seismic data telemetry 42 Within an improved
`module 60. The module 60 is adapted to be installed in
`existing systems, to save on retro?t costs, While providing
`enhanced operating capability as the system to Which it is
`attached is upgraded. This permits usage of currently
`installed equipment, such as the same sections of streamer
`cable, birds, and other external devices, Which provides an
`advantage to those upgrading seismic exploration systems.
`A relay 62 provides tWo modes of operation. A?rst mode
`of operation, shoWn in FIG. 4A, is referred to as normal or
`standard mode since, in this mode, the improved module 60
`operates in the same mode as module 46, With the tWisted
`pair bus 44 passing through the module 60 With no com
`munication With the other circuits in the module. Upon loss
`of poWer, the relay 62 fails to the position depicted in FIG.
`4A.
`In the enhanced mode, shoWn in FIG. 4B, the relay 62 is
`sWitched and the signal on the tWisted pair bus 44 is fed into
`a modem 64. In this mode of operation, other modi?cations
`to the electronics on the vessel for controlling, receiving,
`and transmitting data are required in order to handle the
`alternate data paths in the normal and enhanced modes of
`operation. The modi?cations are described beloW, in greater
`detail.
`The relay 62 is controlled by a command module 66. If the
`command module 66 loses poWer or receives “off” logic, the
`relay 62 is also non-energiZed (i.e., normal mode). This is
`accomplished by selecting a relay With the normally closed
`contacts used for normal mode, and poWer for the relay is
`taken from circuit poWer.
`In addition, the command module 66 interprets signals
`coming from the vessel 40 (See FIG. 2). If the signal to
`operate in the enhanced mode is sent from the vessel, then
`the relay 62 is energiZed. LikeWise, a command to operate
`in the normal mode causes the relay to be non-energiZed.
`The advantage to this is that poWer loss, or the seismic
`telemetry system not being available or malfunctioning, Will
`not fully disable the external device system, since the
`external devices are normally battery equipped. The external
`device system can operate in a conventional manner With
`conventional equipment until such time as the cable is again
`poWered and commands sent to operate in the enhanced
`mode.
`In FIG. 4B, the relay 62 is shoWn energiZed and thus the
`module 60 is in the enhanced mode. NoW in the enhanced
`mode, each segment of the tWisted pair bus betWeen mod
`ules 60 is isolated from all other similar segments of the
`tWisted pair. NoW each module 60 has a relatively short,
`dedicated bus coupling the module 60 With a dedicated
`external device 48. Operation of the streamer cable is more
`reliable in this mode, since the any fault such as a short in
`any one segment of the cable Will not effect any other such
`segment. Fault isolation along the streamer is also much
`easier in this mode.
`
`Ex. PGS 1037
`
`

`

`6,011,753
`
`5
`Each module 60 noW assumes responsibility for relaying
`communications to and from the external devices 48 located
`on its local segment of the tWisted pair bus 44. Because the
`module 60 has high speed communications optimiZed for
`large amounts of data (typically 14 megabits per second),
`sending single bytes at the rates required by the external
`devices 48 (2400 bits per second) can be handled as sub
`channels. Each byte of data sent by the vessel to a particular
`external device is sent to all modules 60 over the seismic
`data telemetry line 42. Each module simultaneously receives
`the data in its command module 66, sends it to a module
`status/control unit 68, Which in turn sends the data to a
`Universal Asynchronous Receiver/Transmitter (UART) 70.
`In general, the UART 70 receives a byte of data from an
`input/output (I/O) bus such as the module status/control unit
`68 at computer or system clock speed, then at a much sloWer
`speed it sends a start bit, a number of bits of data, and a stop
`bit to the sWitch via the modem 64. UARTs are Well knoWn
`in the art, such as an Intel 16550, and may also be found
`embedded in a microprocessor or implemented in the ?rm
`Ware of a microprocessor. The serial output of the UART is
`set to the 2400 bits per second of the external device 48 and
`sent to the modem 64. The modem takes the serial data and
`drives the tWisted pair in the preferred modulation scheme.
`This scheme may be FSK as described above.
`The external device 48 receives this data in a conventional
`manner. Upon receiving a recogniZed message in the form of
`a sequence of bytes, the external device can be commanded
`to carry out a speci?ed function or send back data.
`Speci?cally, these devices are addressable so that broadcast
`messages can address a single device on any bus.
`For data How in the other direction, data sent from the
`external device 48 is received by the modem 64, converted
`to a digital serial data stream, and decoded to bytes by the
`UART 70. The UART 70 receives data one bit at a time until
`the entire byte is assembled. It then generates an interrupt to
`the seismic data telemetry portion of the system so the
`system Will read the neW data from the UART. The byte is
`communicated to the local data transmitter unit 72 via the
`module status/control unit 68. The local data transmitter unit
`72 is then responsible for embedding the 2400 baud data into
`the 14-megabit per second stream to the vessel via a data
`unit 74.
`Since data packets are identi?able as to Which module 60
`originated them (so that the seismic data can be correctly
`mapped), the data corresponding to external devices 48 may
`also be inferred.
`The concept that there are multiple parallel paths back to
`a recorder in the 20—60 modules of the system alloWs
`external devices to communicate back to the vessel in
`parallel, a signi?cant improvement over existing systems.
`By broadcasting a global message. i.e., one addressed to all
`devices, all devices can be made to transmit back simulta
`neously or in groups. For example, one may have one bird
`and one compass associated With each module local bus, i.e.,
`a segment of the tWisted pair bus 44. In a typical system of
`40 modules, a group of 40 birds can ?rst be interrogated as
`to depth, then a group of 40 compasses can be interrogated
`as to heading. In a conventional system, this Would take 80
`separate commands to interrogate to 80 devices and Wait for
`80 replies in sequence due to the shared nature of the long
`bus 44 of FIGS. 2 and 3.
`The above description describes the basic operation of the
`preferred form to the invention. The present invention is also
`adaptable to different lengths of cable, distance betWeen
`modules, and lengths of the short bus, for greater ?exibility
`
`10
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`25
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`30
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`35
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`45
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`
`65
`
`6
`of an entire streamer system. In place of a conventional
`seismic data bus, a ?ber optic or other telemetry means With
`greater band Width may be used, since a large number of
`external devices may be transmitted to and/or received from
`in parallel. Also, With a properly implemented multiplexing
`scheme or different modulation schemes, different bit rates
`for seismic telemetry and external device communication
`telemetry may be used.
`As neW external devices are developed, the present inven
`tion provides the capability to incorporate the neW devel
`opments into existing streamers having this invention
`installed. Different modules having alternate embodiments
`may be included Which alloW introduction of auxiliary data
`to be transmitted betWeen the vessel different types of
`external device.
`By segmenting the tWisted pair bus into small lengths, it
`becomes feasible to couple external devices directly to the
`bus, rather than through coils as in the current state of the art.
`This invention is also applicable to seismic cable telemetry
`systems other than marine, such as land and/or ocean bottom
`cables. Furthermore, cable data other than seismic may be
`handled Where loW speed auxiliary data may be added to an
`existing high speed data stream.
`As previously mentioned, certain modi?cations to the
`controller aboard the vessel or elseWhere are required to
`accommodate this invention. In the current state of seismic
`arts, systems generally employ multiple streamers (i.e. up to
`16) and bird lines sometimes go to gun strings. Bird manu
`facturers such as Syntron, Digicourse generally furnish
`“controllers” aboard the vessel Which are computers
`equipped With multiple modem ports, one port for each
`streamer/bird line that the controller may communicate With.
`A modem port consists of a modem and UART Which, for
`outbound commands from the computer to the external
`devices, serialiZe and encode the data as previously
`described. For inbound data, the data is decoded,
`deserialiZed, and communicated to the CPU of the control
`ler. The CPU responds to user commands and forWards
`speci?c setup commands to the external devices.
`Periodically, the CPU sends query commands to the external
`devices and receives data in reply from the devices indicat
`ing heading, depth, Wing angle, and acoustic transit times.
`The data is processed and forWarded to navigation systems
`and logging devices. There is also a local screen display on
`the vessel, generally graphical With selectable vieWs to
`report this information.
`KnoWn seismic recorders issue commands and receive
`data from individual streamers. The data is serial but trans
`mitted at much higher data rates than the data on bird lines.
`Therefore, the commands and data must be repeated at
`intervals along the streamer such as intervals betWeen mod
`ules. The recorder receives a complex set of serialiZed data,
`consisting of preamble, data, source address, error checking
`information, as Well as module information such as internal
`temperature, pressure, poWer supply voltage and current,
`and serial number. Frequently, this information is sent in a
`multiplexed format Where the data may span a period of
`time.
`In the present invention, bytes to and from external
`devices just become another piece of information multi
`plexed into the complex stream of data already being sent to
`and received from the modules. The logic circuits and
`processors contained Within the recorder process the incom
`ing streamer complex data stream and extract the various
`parts and direct them to the correct destination. In practice,
`one may buffer an entire message (a combination of, for
`
`Ex. PGS 1037
`
`

`

`6,011,753
`
`7
`example, 4 to 32 bytes from an external device) from each
`module into temporary memory. Then, the completed mes
`sage can be forWarded to the controller via a network link
`(i.e. ethernet 10Base-T) for processing of content. This
`requires the controller to accept ethernet input and the input
`to be substituted for the modem port output. Likewise, by
`sending outbound commands to the recorder, the recorder
`Would embed these commands into the outgoing streamer
`command signal. Both the modem ports and the ethernet
`connection may be retained to facilitate using either normal
`mode or enhanced mode, respectively. The detection of
`ethernet data or modem data is handled automatically in this
`arrangement.
`Apart of the recorder may also be programmed to process
`external device data and display the data on the screens
`normally used for streamer information, thus replacing the
`controller. The recorder forWards data to navigation and
`logging systems, and periodically sources the query com
`mands.
`The principles, preferred embodiment, and mode of
`operation of the present invention have been described in the
`foregoing speci?cation. This invention is not to be construed
`as limited to the particular forms disclosed, since these are
`regarded as illustrative rather than restrictive. Moreover,
`variations and changes may be made by those skilled in the
`art Without departing from the spirit of the invention.
`I claim:
`1. A system to control and monitor external devices
`external to a seismic cable behind a vessel and Wherein each
`of the devices is connected to the cable through an associ
`ated magnetic coil coupling, the system comprising:
`a. a plurality of seismic data telemetry conductors, each of
`the plurality of seismic data telemetry conductors com
`prising
`i. a command line outbound from the vessel, and
`ii. a data transmission line inbound toWard the vessel;
`b. a plurality of modules, With one of the plurality of
`modules betWeen each of the plurality of data telemetry
`conductors;
`c. a plurality of control conductors, each control conduc
`tor providing control to one of a plurality of devices
`external to the seismic cable, Wherein each of the
`plurality of control conductors is coupled to an asso
`ciated module; and
`d. a sWitch in each of the plurality of modules to selec
`tively connect one of the plurality of control conductors
`to an associated data telemetry conductor.
`2. The system of claim 1, Wherein the sWitch in each of
`the plurality of modules receives operational poWer from an
`associated control conductor.
`3. The system of claim 2, Wherein the sWitch in an
`unpoWered condition connects control conductors in series.
`4. The system of claim 1, Wherein the seismic cable is a
`marine seismic streamer.
`5. The system of claim 1, further comprising a modem
`selectively coupleable betWeen a control conductor and a
`seismic data telemetry conductor by a sWitch.
`6. The system of claim 5, further comprising a command
`unit in each module.
`7. The system of claim 6, Wherein the command unit
`operates to control the position of the sWitch.
`8. The system of claim 6, further comprising a module
`status/control unit coupled to the command unit to receive
`communications from the command unit directed to an
`external device.
`
`10
`
`15
`
`25
`
`45
`
`55
`
`65
`
`8
`9. The system of claim 8, further comprising an asyn
`chronous receiver/transmitter coupled betWeen the module
`status/control unit and the modem to manipulate data con
`?guration betWeen one of the plurality of seismic data
`telemetry conductors and an external device.
`10. The system of claim 1, Wherein the sWitch is further
`adapted to selectively connect control conductors in series.
`11. The system of claim 1, further comprising an electro
`magnetic coil coupled to each of the plurality control
`conductors to communicate With each of the external
`devices.
`12. A method of controlling an external device external to
`a seismic cable, the external device connected to the cable
`through an associated magnetic coil coupling, the cable
`having a seismic data telemetry cable and a control conduc
`tor in communication With the seismic data telemetry cable,
`comprising the steps of:
`a. selectively and reversibly segmenting the control con
`ductor to isolate the external device from all other
`external devices external to and electrically coupled to
`the seismic cable; and
`b. sending a command signal to the external device
`through the seismic data telemetry cable.
`13. The method of claim 12, further comprising the steps
`of:
`a. receiving the command signal from the seismic data
`telemetry cable into an asynchronous receiver trans
`mitter in byte form;
`b. con?guring the byte form command signal into a serial
`form signal; and
`c. transmitting the serial form signal to an external device
`through a modem.
`14. The method of claim 12, further comprising the steps
`of:
`a. receiving a communication signal from an external
`device in serial form;
`b. con?guring the serial form signal into byte form; and
`c. transmitting the byte form signal to the seismic data
`telemetry cable.
`15. The method of claim 12, further comprising the step
`of selectively and reversibly connecting the segmented
`control conductor in series.
`16. Asystem for controlling a device external to a seismic
`cable having a seismic data telemetry cable and a control
`conductor in communication With the seismic data telemetry
`cable, the system comprising:
`a. a segmented control conductor Which isolates the
`device from other devices external to and electrically
`coupled to the seismic cable; and
`b. means for conducting a command signal to the external
`device from the seismic data telemetry cable.
`17. The system of claim 16 Wherein the means for
`conducting a command signal further provides means for
`conducting data from the external device to the seismic data
`telemetry cable.
`18. The system of claim 16 Wherein the means for
`conducting a command signal to the external device com
`prises a modem and a universal asynchronous receiver/
`transmitter betWeen the seismic data telemetry cable and the
`external device.
`
`Ex. PGS 1037
`
`