Abstract: A downhole networking interface unit provides conversion between multiple native format signals of downhole instruments to power line communication messages exchanged with a controller positionable at the surface of a wellbore. Certain aspects and features provide methods of power line communication. In one aspect, a computing device may send and receive messages in a power line communication format over a cable to and from at least one downhole device. The computing device may send and receive messages in the power line communication format to and from a network interface unit that can be coupled to the cable. The network interface unit may have multiple interfaces for communicating downhole using differing types of native signals for differing types of downhole devices such as sensor, instruments, and inductive couplers.

Abstract: A method is provided for detecting power of a periodic signal in a band of interest of the periodic signal having a predetermined bandwidth. The method includes determining frequencies of multiple tones in the periodic signal, respectively; receiving the periodic signal at a signal analyzer; selectively measuring power values at the frequencies of the multiple tones; and determining a band power of the periodic signal over the predetermined bandwidth by summing the power values at the frequencies of the multiple tones.

Abstract: Embodiments of the disclosure can include systems, methods, and devices for determining saturation pressure of an uncontaminated fluid. Downhole saturation pressure measurements and downhole OBM filtrate contamination of a contaminated fluid may be obtained and a relationship may be determined between the saturation pressure measurements and OBM filtrate contamination. The relationship may be extrapolated to zero OBM filtrate contamination to determine the saturation pressure of the uncontaminated fluid. In some embodiments, OBM filtrate contamination may be determined from downhole saturation pressure measurements during pumpout of a fluid.

Abstract: Disclosed herein are various telemetry systems and methods suitable for communicating a cylindrical volume of formation property measurements to the surface. Some system embodiments include a downhole processor coupled to a telemetry transmitter. The downhole processor determines a compressed representation of the formation property measurements and/or selects a subset of the measurements for transmission uphole. The subset selection can be based on selected radial distances having characteristics that potentially indicate features of interest to a user. Such features include bed boundaries, and the characteristics include sinusoidal variation as a function of azimuth, large changes in this sinusoidal variation versus radial distance, or inversion suggesting the presence of a bed boundary.

Abstract: Aspects of the disclosure can relate to an adapter for power and communication connections between electronic devices in a drill string. In embodiments, the adapter can include a first terminal configured to couple with an output terminal of a first tool and a second terminal configured to couple with an input terminal of a second tool. The adapter can further include a power converter that adjusts a voltage received at the first terminal and supplies the adjusted voltage to the second terminal and a communications adapter that converts a signal format of a communications signal received at the first terminal to a second signal format for the second terminal.

Abstract: A sensor system includes a controller and sensors. The controller is to transmit a signal. The sensors are connected to the controller in series via at least one cable to sequentially transfer the signal transmitted from the controller via the at least one cable.

Abstract: A system for determining a characteristic of an oil well includes a signal source to generate an excitation signal during a first time duration and to generate a local oscillator signal during a second time duration. The system further includes a directional coupler, and a resonator disposed in an annulus of an oil well to receive the excitation signal through the directional coupler. The system also includes a mixer to receive a resonator signal from the resonator through the directional coupler, to receive the local oscillator signal, and to generate a mixer output signal based on the resonator signal and the local oscillator signal. The system further includes a filter to filter the mixer output signal to produce an intermediate frequency signal having an intermediate frequency, and a processor to determine a pressure or a temperature experienced by the resonator based on the intermediate frequency signal and the excitation signal.

Abstract: A system and method for transmitting data over a three phase power system between a surface and a sub-surface location. A first power supply providing a first AC power signal and a second power supply providing a second AC power signal are at the surface. A first powered module and a second powered module which provides a data communications signal are at the sub-surface. A cable connection is provided between the surface and the sub-surface to transmit the power and data communication signals. The data communications signal provides an indication of power applied to the second powered module and a power signal is varied in response to the applied power. The invention finds specific application monitoring down hole equipment such as an electrical submersible pump in a wellbore.

Abstract: A sensor with integrated mechanical transducing and temperature monitoring capability is provided. The sensor includes housing containing a transducer, a temperature sensor with associated bias, a summing circuit, and a two-wire cable connector. The transducer is operable to output a dynamic transducer waveform that corresponds to dynamic mechanical perturbations sensed by the transducer. The temperature sensor is operable to output a quasi-static temperature waveform that corresponds to temperatures sensed by the temperature sensor. The summing circuit is operable to combine the transducer waveform and the temperature waveform into a composite modulated voltage bias output signal or a modulated current bias output signal. The two-wire cable connector is accessible on an outside of the housing and is connectable to a two wire cable that delivers power to the sensor from a power source and delivers the composite output signal from the sensor to a remote data acquisition circuit.

Abstract: According to one aspect, embodiments of the invention provide a method for providing power to a distributed sensor system, the method comprising providing power from at least one port of an interface unit to a first port of a first sensor unit of at least one of a plurality of sensor strings, powering up the first sensor unit, forwarding power from a second port of the first sensor unit to a first port of a second sensor unit of the at least one of the plurality of sensor strings, powering up the second sensor unit, monitoring the plurality of sensor strings for a fault condition, and in response to detecting a fault condition in a first sensor string of the plurality of sensor strings, providing power from a second one of the plurality of sensor strings to the first sensor string.

Abstract: The present invention relates to a downhole well-operation system for operating a driving unit and a logging tool downhole and transmitting well-logging data from at least one logging tool to a surface data acquisition system by means of a wireline. The system comprises a surface transceiver, a wireline, a downhole transceiver, a logging tool, and a driving unit, wherein the downhole transceiver is coupled to the surface transceiver via the wireline and communicates to the surface transceiver using orthogonal frequency division multiplexing to transmit data via the wireline by modulating a Pulse Width Modulated (PWM) signal to the wireline by means of a transistor bridge, while the driving unit and at least one logging tool is powered by the wireline. Furthermore, the invention relates to a downhole tool.

Abstract: A multitone nonlinear radar system (and a method of operating such a system) comprising a transmitter that transmits a signal comprising at least two predetermined frequency components; a receiver operating to receive return signals comprising harmonics of at least two predetermined frequencies, combinations of the at least two predetermined frequency components, and combinations of the harmonics of the at least two predetermined frequency components that are within a predetermined selected frequency range that has been predetermined to enable detection and/or classification of an electronic device; at least one antenna operating to transmit and receive electromagnetic radiation operatively connected to the transmitter and receiver; the receiver comprising at least one high pass filter for attenuating linear reflections at the two predetermined frequencies, and an analyzer; whereby electronic devices may be detected and identified by analyzing return signals within a predetermined frequency range.

Abstract: An apparatus that is usable with a well includes a first equipment section that includes a first inductive coupler and a second equipment section that includes a second inductive coupler. The second equipment section is adapted to be run downhole into the well after the first equipment section is run downhole into the well to engage the first equipment section. A mechanism of the apparatus indicates when the first inductive coupler is substantially aligned with the second inductive coupler.

Abstract: Gamma pulse telemetry. At least some of the illustrative embodiments are methods including: reading data associated with a borehole penetrating an earth formation; encoding the data in a first plurality of gamma bursts, the encoding by an encoding system coupled within the drill string, and where the each gamma burst travels a first distance along the borehole; receiving the first plurality of gamma bursts by a receiver system coupled within the drill string; and decoding the first plurality of gamma bursts and thereby recovering the data.

Abstract: Provided are systems and methods for ground fault immune data measurement system for electric submersible pumps. A data measurement system coupled to the ESP includes a surface unit coupled to a 3-phase power cable for providing power to a 3-phase motor of the ESP and a downhole unit coupled to the motor of the ESP and located downhole in a well. The downhole unit includes sensor and is configured to generate frequency modulated carrier signals for carrying the sensor data to the surface unit. Each of the frequency modulated carrier signals carries identical sensor data and is modulated to a different frequency. The carrier signals are shunted across the motor windings of the ESP motor and onto the 3-phase power cable via a capacitive coupling. Additionally, another carrier signal carrying control data may be transmitted from the surface unit to the downhole unit.

Abstract: Methods and apparatus for fast sweeping a spectral bandwidth in order to distinguish among signals received from effectively wavelength division multiplexed (WDMed) and time division multiplexed (TDMed) optical components on a single fiber. For some embodiments, a method for interrogating optical elements having characteristic wavelengths spanning a sweep range is provided. The method generally includes introducing a pulse of light, by an optical source, into an optical waveguide to interrogate at least a first set of optical elements having different characteristic wavelengths by performing a sweep of wavelengths over a period of the pulse, wherein the period is less than a round-trip time for light reflected from an optical element closest to the optical source to reach a receiver and processing the reflected light to determine a parameter based on the times at which signals are received.

Abstract: Pressure measurements are made using a pressure sensor in the proximity of the drillbit during drilling operations. A filtered version of the pressure measurements is provided to a pulser for a mud-pulse telemetry system so as to cancel pressure variations due to drilling noise while a telemetry signal is being sent. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: Job monitoring methods and apparatus for logging-while-drilling equipment are disclosed. A disclosed example method includes identifying a downhole scenario based on a property of an underground geological formation, selecting a first telemetry frame type based on the identified downhole scenario, conveying an identifier representative of the selected first telemetry frame type to a downhole fluid sampling tool, and receiving a first telemetry data frame from the downhole fluid sampling tool, the telemetry data frame containing fluid analysis parameters for a fluid, and being constructed in accordance with the selected first telemetry frame type.

Abstract: Systems and methods of signal transmission and measuring for sensors employing a transmission medium are provided. In one embodiment, a method may comprise measuring a first monitored condition to generate a first monitored condition signal; converting the first monitored condition signal to a first frequency modulated signal having a first frequency; generating a second frequency modulated signal having a reference frequency; transmitting the first frequency modulated signal and the second frequency modulated signal using time division multiplexing; and wherein a first ratio of the first frequency and the reference frequency is associated with the first pressure.

Abstract: An embodiment of a method for limiting the probability of failure on demand of a subsea test tree (“SSTT”) includes the steps of providing a safety shut-in system for actuating a safety valve of the SSTT, the safety shut-in system including a surface control station positioned above a water surface connected via an umbilical to a subsea control system positioned below the water surface to actuate the safety valve; and diagnostically testing the safety shut-in system without actuating the safety valve.

Abstract: Apparatus and methods for controlling and communicating with one or more tools in a downhole tool string including a tractor, an auxiliary tractor tool, a logging tool, a safety sub, a release mechanism, a unit containing sensors for monitoring downhole conditions, a setting tool, and a perforating gun. Also provided are apparatus and methods for controlling and communicating with one or more perforating guns, release devices, and explosive devices in a string to be lowered into a wellbore. Control and communication are accomplished by sending signals from the surface to control switches in the control units on the tool, with redundant switches for safety, to state machines in the respective control units, each state machine returning a signal verifying switch status to the surface. Control and power functions are accomplished with voltage of different polarities for safety.

Abstract: The present disclosure relates to a method to determine a clock signal when separate clocks are used. In one embodiment, a disciplined clock system comprising an update subsystem and a synthesis subsystem is provided. A first clock phase estimate is provided to the update subsystem and used, along with the update subsystem, to determine a frequency offset estimate and a phase offset estimate. The clock signal is determining using the frequency offset estimate, the phase offset estimate, and the synthesis subsystem. Alternatively, two clocks can be synchronized by generating a signal associated with a first clock; modulating the signal; transmitting the modulated signal; receiving the modulated signal by a receiver associated with a second clock; correlating the received signal; determining the time of arrival of the received signal; determining the time difference between the two clocks; and synchronizing the two clocks.

Abstract: An electronic module for use as a subsea electronic module for an underwater fluid extraction well, wherein a local area network enables communication within the module, the local area network including a plurality of interfaces with components of the network, and wherein the interfaces comprise capacitive coupling interfaces.

Abstract: Systems and methods for reliably communicating data between surface and downhole equipment over a power cable, regardless of the length of the power cable, wherein a transmitter modulates a common data stream onto multiple high frequency carrier signals, each of which has a different frequency. Each of the different frequencies is best suited to communication over a different length of cable. The resulting modulated high frequency data signals are impressed on the power cable and are recovered from the cable by a receiver. The receiver is configured to recover signals at each of the different carrier frequencies, at least one of which should be transmitted with little enough attenuation and interference that the data stream can be accurately recovered from the corresponding modulated high frequency data signal.

Abstract: Job monitoring methods and apparatus for logging-while-drilling equipment are disclosed. A disclosed example method includes obtaining a fluid associated with an underground geological formation, analyzing the fluid with one or more sensors to form respective ones of sensor outputs, identifying a downhole scenario associated with the fluid based on the sensor outputs, the identifying being performed while the sensors are within the underground geological formation, and selecting a telemetry frame type based on the identified downhole scenario.

Abstract: An electronic module for use as a subsea electronic module (SEM) for an underwater fluid extraction well, as provided. An example of such an SEM includes a plurality of substantially planar electronics cards to operate devices in the SEM. The cards are arranged in a stack such that major faces of each card are oriented substantially parallel to, and coaxial with, major faces of the other cards in the stack. The SEM also includes a substantially planar switch card orientated relative to the stack such that its major faces are oriented substantially parallel to a main axis of the stack and orthogonal to the orientation of the major faces of the electronics cards within the stack. The switch card includes a first Ethernet switch blade configured to control traffic on a LAN area network and a second Ethernet switch blade configured to control traffic on a second LAN.

Abstract: In one aspect of the present invention, a method for tool string communication comprises the steps of providing a downhole tool string with at least two downhole LWD/MWD instruments in electrical communication with a downhole telemetry system. The instruments are capable of generating at least one data packet assigned a priority. The tool string is deployed in a wellbore and then the priority of the data packet is changed.

Abstract: An apparatus includes a transmission line for deployment in a well, and a driver to transmit signals over the transmission line. The driver includes a field-effect transistor, and an operational amplifier to control the field-effect transistor, where the operational amplifier and field-effect transistor cooperate to form a voltage-to-current converter.

Abstract: Systems and methods for reliably communicating data at high data rates between surface and downhole equipment over a power cable by multiplexing data, modulating the data onto orthogonal carrier frequencies, communicating the modulated carrier signals over the power cable, recovering of the modulated signals, and demodulating the data stream from the recovered signal. One embodiment comprises a system that includes surface equipment connected by a power cable to an ESP system that has a gauge package connected to it. The gauge package uses a high-temperature DSP to perform the data processing associated with OFDM communications.

Abstract: A method for the time-serial transmission of received signals of electroacoustic transducers (11), which are placed at different transducer locations (13) of a spatially spread receive arrangement (10), to a signal processing unit (12), in which at each transducer location (13) the received signals are digitized by an electronic module (20), and the digitized received signals are switched onto a data line (14, 15, 16) leading to the signal processing unit (12) in the timing pattern of a synchronization clock. To obtain a high data rate with undisturbed data transmission, the intrinsic switching-time errors of the electronic modules (20) are measured with respect to the switching times defined by the timing pattern, and compensated for at the transducer locations (13) by individual time delay of the signals to be switched.

Abstract: A receiver in an impulse wireless communication. The receiver (300) includes a pulse-pair correlator (304) that receives a signal (316) and divides it into two signals for paths. One of the signals is input to signal multiplier (312) while another signal is delayed by a delay unit (310). The signal multiplier (312) multiplies the received signal (316) by a delayed signal (318). An integrator (314) integrates an output signal (322) over a designated period of time. An adding module (306) sums an output signal (324) from the integrator (314). An acquiring module (308) compares an summing-up output (326) from the adding module (306) with a predetermined threshold value to detect the existence of a transmitting-standard preamble.

Abstract: A drilling system utilizing a plurality of independent telemetry systems. The drilling system uses a drill collar as a pressure housing for downhole components of the system. One or more sensors are disposed within the pressure housing. These sensors can be MWD sensors, LWD sensors, or both MWD and LWD sensors. A plurality of independent borehole telemetry systems is used to telemeter sensor response data to the surface of the earth. Each sensor cooperates with a downhole component of at least one of the independent telemetry systems. The plurality of telemetry systems can be of the same type, such as a mud pulse systems. Alternately, the telemetry systems can be of different types including a mud pulse system and an electromagnetic system.

Abstract: A motor absolute position signal processing apparatus connected to a signal processor and an optical encoder of a motor control system includes first and second switches, a signal integration amplifier, first and second separators and an inverter. The first switch is connected with the optical encoder, the second switch with the optical encoder and the first switch, the signal integration amplifier with the first and second switches, the first separator with the signal integration amplifier and the signal processor, and the second separator with the signal processor. An input end of the inverter is connected with the second separator and an output end with the second switch. The signal processor outputs an enable signal to be processed by the inverter for switching the first or second switch. The signal integration amplifier processes and transmits two sets of differential signals SIN;/SIN and COS;/COS of the optical encoder to the signal processor.

Abstract: A motor position signal processing apparatus electrically connected to a signal processor and an optical encoder of a motor control system includes a first switch, a second switch, a first signal integration amplifier, a first separator, a second signal integration amplifier, a second separator, a third signal integration amplifier, a third separator, a fourth separator and an inverter. An enable signal outputted by the signal processor is processed by the inverter to switch the operation to the first switch or the second switch. An incremental signal outputted by the optical encoder, a motor mechanical position and a reset correction signal are processed by the first, second and third signal integration amplifiers and transmitted to the signal processor for controlling the operation of a motor.

Abstract: An electronic module for use as a subsea electronic module for an underwater fluid extraction well, wherein a local area network enables communication within the module, the local area network including a plurality of interfaces with components of the network, and wherein the interfaces comprise capacitive coupling interfaces.

Abstract: Subterranean oilfield sensor systems and methods are provided. The subterranean oilfield sensor systems and methods facilitate downhole monitoring and high data transmission rates with power provided to at least one downhole device by a light source at the surface. In one embodiment, a system includes uphole light source, a downhole sensor, a photonic power converter at the downhole sensor, an optical fiber extending between the uphole light source and the photonic power converter, and downhole sensor electronics powered by the photonic power converter. The photonic power converter is contained in a high temperature resistant package. For example, the high temperature resistant package and photonic power converter may operate at temperatures of greater than approximately 100° C.

Abstract: Enhanced symbol synchronization methods suitable for use in narrowband orthogonal frequency division multiplexed (OFDM) telemetry systems. In at least some embodiments, a logging while drilling (LWD) tool assembly communicates with the surface using low frequency electromagnetic (EM) signals. The telemetry transmitter employs OFDM modulation to fully exploit the narrow range of available bandwidth, resulting in signals that have relatively long frames. At the surface a receiver digitizes the receive signal and applies an enhanced symbol synchronization technique to identify frame boundaries before demodulation is attempted. The enhanced symbol synchronization technique employs a pulse train filter to clean up a cyclic prefix correlation signal that otherwise behaves badly in the narrowband regime. The improved timing information from the enhanced symbol synchronization significantly reduces the error rate in the demodulated signal.

Abstract: A communications system includes a first wireless communications system configured to provide wireless communications over a first frequency band, and a second wireless communications system configured to provide wireless communications using at least a portion of the first frequency band. The system includes an inter-system communications link between the first wireless communications system and the second wireless communications system. The inters-system communications link is used to coordinate the use of the first frequency band. The system further includes an interference reducer configured to reduce interference between the first wireless communications system and the second wireless communications system. Related methods are also disclosed.

Abstract: In one aspect of the present invention, a method for tool string communication comprising the steps of: providing a downhole tool string with at least two downhole LWD/MWD instruments in electrical communication with a downhole telemetry system, the instruments being capable of generating at least one data packet assigned a priority; then deploying the tool string in a well bore; and then changing the priority of the data packet.

Abstract: A method of measuring while drilling includes positioning at least one sensor downhole; and transmitting sensed data while drilling from the at least one sensor to surface without storing the sensed data downhole and system.

Abstract: Token authorized node discovery between a plurality of store-and-forward nodes in a downhole networking environment and respective applications for data processing and communication are described herein.

Abstract: A system for communicating information in a borehole between tool assemblies in a tool string includes receiving an information signal and separating a first signal that may be a power and low speed signal. A second signal is separated and demodulated from the information signal. The first signal and second signal are transmit to electronic devices that process data from an earth formation. After the first and second signals are transmit to one or more electronic devices, the signals are modulated and/or filtered and then combined into the information signal. The first signal is at one frequency and the second signal is at a different frequency. The apparatus includes a main signal line that couples to a second signal line and third signal line in the tool assembly.

Abstract: A communications system employing discrete multi-tone (“DMT”) modulated signals on a communications channel formed by inductively-coupled pipe. In one embodiment, the communications system includes a string of wired pipe joints that couple a transmitter to a receiver. Each pipe joint in the string possesses threaded ends configured for mechanically connecting with other pipe joints, a electrical or inductive coupler at each threaded end, and an insulated conductor that electrically connects the couplers. The transmitter and receiver communicate via DMT modulated signals transported by the wired pipe string. The system may further include multiple repeaters in the string. Each repeater may be configured to receive a DMT-modulated signal, to recover information from the DMT-modulated signal, and to retransmit the information in the form of a DMT-modulated signal.

Abstract: Improved communication systems and methods are disclosed. In one embodiment, a downhole communications system comprises a downhole transceiver and a surface transceiver. The surface transceiver receives a discrete multi-tone (DMT) modulated uplink signal from the downhole transceiver, and transmits a downlink signal to the downhole transceiver using a modulation method determined by the transceivers as communications are initiated. The downlink modulation methods supported by the surface transceiver may include DMT modulation and quadrature amplitude modulation (QAM). The modulation mode selection may be based on measured channel characteristics, on proposed data rates, or on other predetermined parameters. The uplink and downlink signals may be communicated over a shared transmission mode on multiconductor cable or wired pipe, and alternatively the uplink and downlink signals may be communicated over separate transmission modes.

Abstract: Self-detection of a modulating carrier and an optimum carrier in a downhole telemetry system. A method of detecting a carrier frequency in a downhole wireless telemetry system includes the steps of: transmitting from a first telemetry device a message modulated on a predetermined carrier frequency; receiving at a second telemetry device signals including multiple frequencies; and selecting from among the multiple received frequencies the predetermined carrier frequency on which the message is modulated. A method of detecting a usable downhole wireless telemetry system carrier frequency includes the steps of: transmitting from a first telemetry device a message modulated on a carrier frequency; then checking whether a response to the message is received at the first telemetry device from a second telemetry device; and each time the response is not received, repeating the transmitting and checking steps with an incremented carrier frequency.

Abstract: A multiplexing system is provided for a plurality of sensors disposed in a tank containing a potentially explosive environment and excited from a common excitation circuit outside of the tank through a corresponding plurality of signal lines that penetrate the tank. The multiplexing system comprises: a multiplexer switch for each sensor, each multiplexer switch disposed outside of the tank in series with the corresponding signal line between the common excitation circuit and the corresponding sensor in the tank.

Abstract: Methods and systems for transmitting and receiving a discrete multi-tone (DMT) modulated signal in a fluid. Some illustrative embodiments may be a method comprising transforming an input data series into an information-carrying signal (the information-carrying signal carrying input data from the input data series as modulations of at least one of a plurality of evenly spaced frequency bins), and applying the information-carrying signal to a transducer that converts the information-carrying signal into pressure variations within a fluid.

Abstract: A communications system employing discrete multi-tone (“DMT”) modulated signals on a communications channel formed by inductively-coupled pipe. In one embodiment, the communications system includes a string of wired pipe joints that couple a transmitter to a receiver. Each pipe joint in the string possesses threaded ends configured for mechanically connecting with other pipe joints, a electrical or inductive coupler at each threaded end, and an insulated conductor that electrically connects the couplers. The transmitter and receiver communicate via DMT modulated signals transported by the wired pipe string. The system may further include multiple repeaters in the string. Each repeater may be configured to receive a DMT-modulated signal, to recover information from the DMT-modulated signal, and to re-transmit the information in the form of a DMT-modulated signal.

Abstract: Apparatus for conducting geophysical surveys comprising a multiplicity of intelligent electrodes provided on a multi-conductor cable, for receiving a command signal in response to which predetermined electrodes are connected to selected conductors in the cable. Each intelligent electrode is identical in all respects, including its programming, resulting in simplified construction of the cable and easy replacement of the intelligent electrodes. Instead of assigning a unique address code to each switch in a series of take-outs on a multi-conductor cable, each electronic switch is programmed with the same address code. That is, each switch is programmed to be activated when it receives a code command that, for example, is prefaced with a particular address, e.g. the number 1. The second part of the code (y) instructs the switch as to which conductor in the multi-conductor cable is to be connected to the local electrode at the location of the switch.

Abstract: A method and related apparatus for telemetry between downhole devices and surface devices. In particular, the methods and related apparatus may send a first datum of a first parameter in an uncompressed form, and send a second datum of the first parameter in compressed form.