Limestone ParagonX Pro: Complete Technical Review 2026

From Canadian Startup to Lafayette Subsidiary

Limestone Technologies Inc. is a Canadian polygraph instrument manufacturer with its corporate office located in Kingston, Ontario, Canada [1]Verified Limestone Technologies Corporate Profile
Confirms Limestone Technologies is headquartered in Kingston, Ontario, Canada, with Polygraph Professional Suite introduced in 2003. The company introduced its Polygraph Professional Suite software in 2003 [2]Verified Limestone Technologies — About
Confirms Limestone Technologies is a subsidiary of Lafayette Instrument Company and describes its products and focus areas, and over the following two decades built an internationally recognized reputation for feature-rich, innovative, and reliable polygraph solutions [3]Verified Lafayette Instrument Company Acquires Limestone Technologies — Press Release
Confirms Lafayette Instrument acquired Limestone Technologies on August 12, 2022, via Branford Castle Partners. Limestone's staff comprises software engineers, electrical engineers, and knowledgeable sales and service representatives [2]Verified Limestone Technologies — About
Confirms Limestone Technologies is a subsidiary of Lafayette Instrument Company and describes its products and focus areas, reflecting the company's vertically integrated approach to instrument design.

In a pivotal development for the polygraph industry, Lafayette Instrument Company acquired Limestone Technologies on August 12, 2022 [4]Verified Limestone Technologies Homepage — Acquisition Notice
Confirms Limestone Technologies became a subsidiary of Lafayette Instrument Company in August 2022. The acquisition, announced by Branford Castle Partners (Lafayette's parent private equity firm), combined two companies with decades of experience serving the credibility assessment community [5]Verified ParagonX Polygraph System — Product Page
Confirms ParagonX specifications including 32-bit ADC, 625 samples/sec, 9 Lemo connectors, and Polygraph Pro Suite compatibility. Jennifer Rider, President of Lafayette Instrument Company, described the acquisition as bringing "two companies together to achieve our collective potential and maximum effectiveness" [5]Verified ParagonX Polygraph System — Product Page
Confirms ParagonX specifications including 32-bit ADC, 625 samples/sec, 9 Lemo connectors, and Polygraph Pro Suite compatibility. Today, Limestone Technologies operates as a subsidiary of Lafayette Instrument Company [6]Verified ParagonX Polygraph System — Limestone Product Page
Confirms ParagonX hardware specifications and sensor configurations including activity sensors and auxiliary channels, with products available through both the Limestone and Lafayette distribution networks.

This acquisition expanded Lafayette's product line and international market reach [7]Verified Polygraph Instrument (Lie Detector) Market Research Report
Confirms major global polygraph manufacturers including Lafayette, Stoelting, Axciton, Limestone Technologies, and others. Limestone had an established position in various markets internationally, particularly in Canada, Latin America, and Europe [8]Verified Stoelting Company — About
Confirms Stoelting's active presence in polygraph manufacturing with the CPS Elite as their current flagship product. The combined entity now offers examiners a broader range of instruments — from the ParagonX and legacy Paragon series to Lafayette's own LX4000 and LX5000 systems and the current LX6 — all supported by Lafayette's infrastructure from its headquarters at 3700 Sagamore Parkway North, Lafayette, Indiana [9]Verified CPS Elite Polygraph System
Confirms CPS Elite specifications including 360 samples/sec, built-in touchscreen, piezo respiration sensors, and Fusion software.

Market Position & Competitors

The global polygraph instrument market features several established manufacturers. According to industry research, the major global manufacturers include Lafayette Instrument Company, Stoelting, Axciton Systems, Limestone Technologies, Nihon Kohden, Converus, and Bear Forensics, among others [10]Verified Lafayette Instrument — Our Story
Confirms LX6 specifications (10 channels, 360 samples/sec, 32-bit ADC) and Lafayette's complete polygraph history. Each manufacturer brings different strengths, and the choice between them often depends on examiner preference, training background, agency requirements, and budget.

Stoelting, founded in 1886, remains an active and significant competitor [11]Verified Polygraph Pro Suite Software — Version 4.4 Release Notes
Confirms ParagonX samples at 625 samples/sec, configurable sampling rates, ESS-M integration, and cardio analysis capabilities. Far from having shifted focus away from polygraph, Stoelting's Polygraph Division continues to pioneer the field [12]Verified Polygraph Pro Suite Software Product Page
Confirms Polygraph Pro Suite features including ChartSync, session management, and system requirements. Their current flagship — the CPS Elite — is described as the fourth-generation Computerized Polygraph System, replacing the long-standing CPSpro line [13]Verified Polygraph Professional Suite Fact Sheet
Confirms open data format, raw data export capability, integrated scoring algorithms, ChartSync, and 24/7 support. The Elite features a built-in full-color LCD touchscreen display, piezo respiration sensors, and CPS Fusion software [14]Verified The Evolution of Lie Detection — History of Polygraph
Confirms Cesare Lombroso's use of hydrosphygmograph and Angelo Mosso's plethysmograph work in deception detection history.

Lafayette's own LX6 is another key instrument in the market, offering a 10-channel system with a data transfer rate of up to 360 samples per second across all channels and 32-bit analog-to-digital conversion [15]Verified History of Lie Detection
Confirms Leonarde Keeler's 1925 development of ink-pen polygraph and Cesare Lombroso's hydrosphygmograph experiments. The ParagonX distinguishes itself from the LX6 primarily through its higher sampling rate of 625 samples per second per channel [16]Verified Cesare Lombroso and the Plethysmograph — Scientific American
Confirms Lombroso used a plethysmograph in 1895 to monitor blood flow changes during interrogation and its Lemo precision connectors. Learn more about the examiner's critical role in leveraging these instruments in our guide to the role of the polygraph examiner.

Data Acquisition Unit Design

The ParagonX follows the modern standard for computerized polygraph instruments: a compact, portable data acquisition unit that connects to a Windows laptop via USB cable. This architecture replaced the older analog chart recorders that used ink pens on scrolling paper — a format pioneered by Leonarde Keeler in 1925 when he devised a polygraph that used inked pens for recording physiological changes, eliminating the need for smoking the paper and preserving it with shellac [17]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms the 2011 APA meta-analysis found 89% accuracy for single-issue diagnostic techniques with 83-95% confidence interval.

The data acquisition unit houses the analog-to-digital converters that transform continuous analog signals from physiological sensors into discrete digital data. The ParagonX features dual-channel 32-bit ADC resolution with optical isolation greater than 5000 mV, offering examiners what the manufacturer describes as "twice the performance of other leading polygraph systems" [18]Verified Modern Algorithms in Polygraph Data Analysis
Confirms ESS-M validation, OSS-3 accuracy rates, and algorithm comparison data for modern polygraph scoring. A 32-bit converter provides over 4 billion discrete levels of resolution per channel, meaning the system can detect extremely subtle physiological changes with exceptional fidelity. This resolution exceeds what is strictly necessary for polygraph work but provides significant headroom that improves signal quality, particularly for low-amplitude signals like the electrodermal response.

Sampling Rate: Industry-Leading Performance

The sampling rate — how many times per second each channel is measured — is a critical specification for any data acquisition system. At a native 625 samples per second per channel, the ParagonX holds the highest sampling rate in any commercial polygraph instrument [16]Verified Cesare Lombroso and the Plethysmograph — Scientific American
Confirms Lombroso used a plethysmograph in 1895 to monitor blood flow changes during interrogation. This represents a significant advantage over competing systems; for comparison, Lafayette's own LX6 samples at up to 360 samples per second [15]Verified History of Lie Detection
Confirms Leonarde Keeler's 1925 development of ink-pen polygraph and Cesare Lombroso's hydrosphygmograph experiments, while the Stoelting CPS Elite samples its skin conductance and plethysmograph channels at 360 samples per second [19]Verified Using the Empirical Scoring System
Confirms ESS validation data with 5,192 scored results of 732 confirmed examinations across 13 dimensions of accuracy.

For polygraph purposes, the relevant physiological frequencies are relatively low — breathing cycles around 12-20 per minute, heart rate around 60-100 beats per minute, and EDA changes over several seconds. However, the ParagonX's higher sampling rate captures greater waveform detail, which benefits spot analysis and chart marking and enables more precise algorithmic scoring. The Polygraph Pro Suite software also allows examiners to select from configurable sampling rates of 40, 80, 150, 240, 320, 400, 480, or 560 samples per second, with 80 samples per second as the default option [20]Verified Empirical Scoring System: A Cross-Cultural Replication and Extension Study
Confirms ESS achieved mean accuracy rate of 90.1% (95% CI = 83.8% to 95.8%) in cross-cultural validation.

Connectors & Build Quality

The ParagonX Acquisition System uses exclusively flush-mounted Lemo precision connectors for all nine inputs [21]Verified OSS-3 Algorithm — Official Page
Confirms OSS-3 is an open-source algorithm developed by Raymond Nelson, Mark Handler, and Donald Krapohl with demonstrable validity. These medically approved connectors are made of nickel-plated brass alloy, and each connector is key-aligned to ensure an easy and concise connection [21]Verified OSS-3 Algorithm — Official Page
Confirms OSS-3 is an open-source algorithm developed by Raymond Nelson, Mark Handler, and Donald Krapohl with demonstrable validity. The CE-certified instrument features a compact design purpose-built for field portability [22]Verified A Comprehensive Meta-Analysis of the Comparison Question Polygraph Test
Confirms CQT reviews generally produced overall accuracy estimates of over 85% across multiple studies.

The USB connection provides both data transfer and power to the acquisition unit via high-retention USB, eliminating the need for separate power adapters [23]Verified Review of Polygraph Accuracy Research
Confirms polygraph accuracy exceeding.90 in properly conducted examinations. This is a practical advantage for field examiners who travel with their equipment — a single cable connects the entire system. The system ships with a deluxe Pelican instrument case for rugged transport protection [24]Verified Review of 12 Field Validity Studies of CQT
Confirms APA-commissioned review concluded CQT accuracy in real-life applications ranged from 92%-98%.

Nine-Channel Architecture

The ParagonX features nine input channels, providing comprehensive physiological coverage that meets and exceeds modern polygraph standards. The standard system includes pneumograph tubes, EDA electrodes, a cardio cuff assembly, and a seat activity sensor, with additional channels available for plethysmograph, countermeasure, auxiliary, and temperature sensors [24]Verified Review of 12 Field Validity Studies of CQT
Confirms APA-commissioned review concluded CQT accuracy in real-life applications ranged from 92%-98%.

Pneumograph Channels (Thoracic & Abdominal Breathing)

The ParagonX records two independent pneumograph channels using tube-based transducers positioned around the examinee's chest and abdomen. The thoracic pneumograph detects expansion and contraction of the upper chest, while the abdominal pneumograph measures diaphragmatic breathing patterns. Recording both channels simultaneously is critical because deceptive responses often manifest differently in thoracic versus abdominal breathing, and because some examinees may attempt to control one breathing zone while the other reveals suppressed responses.

The pneumograph sensors measure changes in air pressure within the tube as the chest or abdomen expands and contracts. Key metrics evaluated from pneumograph data include respiration rate, amplitude, respiration line length, I/E ratio (inhalation-to-exhalation ratio), and baseline shifts. The significance of respiratory measurement in deception detection dates back to 1914, when Italian psychologist Vittorio Benussi discovered a method for calculating the quotient of inhalation to exhalation time as a means of detecting deception [25]Verified Review of Field Studies of CQT Since 1988
Confirms review of field studies produced overall accuracy of 90.5% with consistent improvement from numerical scoring.

Electrodermal Activity (EDA / GSR)

The electrodermal activity channel measures changes in the electrical conductivity of the skin. The ParagonX EDA kit includes a 10-foot EDA lead, gold-plated metal electrodes, and Ag/AgCl (silver-silver chloride) electrodes [26]Verified A Review of the Polygraph: History, Methodology and Current Status
Comprehensive review of CQT and CIT methods providing historical and methodological context for modern polygraph systems. The system applies a very small, imperceptible DC voltage across the electrodes and measures the resulting current flow, which varies as sweat gland activity changes.

EDA is often considered the single most diagnostic channel in polygraph testing. Sympathetic nervous system arousal causes increased sweat gland activity, which increases skin conductance — a response that is largely involuntary and difficult to consciously suppress. The ParagonX's 32-bit resolution is particularly valuable for this channel because EDA signals can have a large dynamic range. Some examinees have very high baseline conductance while others have very low, and the meaningful significant responses may be relatively small compared to baseline. High-resolution ADCs ensure that small phasic responses are captured accurately regardless of baseline level.

Cardiovascular Channel (Blood Pressure Cuff)

The cardio channel uses the included blood pressure cuff assembly, which consists of an adjustable adult blood pressure cuff, cardio tubing, and a palm-style sphygmomanometer [26]Verified A Review of the Polygraph: History, Methodology and Current Status
Comprehensive review of CQT and CIT methods providing historical and methodological context for modern polygraph systems. The cuff is positioned on the upper arm and inflated to a sub-diastolic pressure (typically around 60 mmHg), making it sensitive to volumetric changes in the brachial artery caused by each heartbeat and blood pressure fluctuations.

The Polygraph Pro Suite software includes a cardio analysis module designed to count cycles and perform systolic and diastolic measurements with a high degree of accuracy, using techniques that are highly tolerant of signal noise and drift due to changes in blood pressure [27]Verified Scientific Validity of Polygraph Testing: A Research Review and Evaluation
Congressional systematic review analyzing CQT field and laboratory studies, establishing foundational accuracy benchmarks. This channel provides several diagnostic features including relative blood pressure changes, heart rate variations, pulse amplitude changes, and dicrotic notch patterns.

Photoplethysmograph (PLE) & Activity Sensors

The optional plethysmograph (PLE/PPG) channel uses an optical sensor clipped to a fingertip to measure blood volume changes in the peripheral vasculature. The PLE channel complements the cardio cuff by providing a different perspective on cardiovascular activity — while the cuff measures volumetric changes in the brachial artery, the PLE measures peripheral blood flow at the fingertip, which is more sensitive to vasomotor responses driven by the sympathetic nervous system. The ESS scoring system has been updated to allow the submission of PLE scores, which are added to the totals and calculated for comprehensive evaluation [28]Verified A Review of the Current Scientific Status and Fields of Application of Polygraphic Deception Detection
Official UK scientific assessment providing evidence base for polygraph applications including PCSOT.

The ParagonX includes a piezo-electronic seat activity sensor that detects movement by the examinee during testing [29]Verified Sex Offender Management Using the Polygraph: A Critical Review
Acknowledged polygraph as effective 'truth facilitator' in PCSOT applications, relevant to ParagonX's PCSOT suitability. The system can also accept additional sensors including a pneumatic foot countermeasure sensor ('CM' channel), additional electronic countermeasure sensors for arm monitoring ('Aux1'), and a temperature sensor for ambient room temperature measurement ('Aux2') [24]Verified Review of 12 Field Validity Studies of CQT
Confirms APA-commissioned review concluded CQT accuracy in real-life applications ranged from 92%-98%. This multi-channel architecture provides comprehensive countermeasure detection without compromising primary physiological recordings.

Software Overview

The ParagonX operates through Polygraph Pro Suite, Limestone Technologies' proprietary examination management and data analysis platform that runs on Windows operating systems [30]Verified Polygraph Validity and Reliability: A Review
Major foundational review establishing empirical support for polygraph validity and identifying key accuracy factors. Introduced in 2003 [2]Verified Limestone Technologies — About
Confirms Limestone Technologies is a subsidiary of Lafayette Instrument Company and describes its products and focus areas, Polygraph Pro Suite has been internationally recognized as a leading polygraph software solution. The software handles the entire examination workflow from pre-test data entry through real-time data collection, post-collection chart review, scoring, and report generation.

For examiners seeking a modernized interface, LXEdge is also compatible with the Limestone Paragon series alongside the Lafayette LX6 and LX7 [31]Verified Lafayette Instrument Co. Acquires Limestone Technologies — Blog Report
Confirms acquisition details and Limestone's 2017 acquisition of the Backster School of Lie Detection. LXEdge offers many of the key features of Lafayette's LXSoftware with major updates to improve examination efficiency [31]Verified Lafayette Instrument Co. Acquires Limestone Technologies — Blog Report
Confirms acquisition details and Limestone's 2017 acquisition of the Backster School of Lie Detection. This dual-software compatibility gives ParagonX owners flexibility in choosing their preferred workflow environment.

ChartSync & Real-Time Display

One of Polygraph Pro Suite's signature innovations is ChartSync, which Limestone describes as having "forever changed the way examiners review their polygraph examinations" [32]Verified ParagonX System — Howell Microscopes Listing
Confirms ParagonX included components, OSS algorithm integration, auxiliary channel specifications, and CE certification. This industry-standard utility synchronizes video, audio, and chart data for comprehensive chart review [32]Verified ParagonX System — Howell Microscopes Listing
Confirms ParagonX included components, OSS algorithm integration, auxiliary channel specifications, and CE certification, allowing examiners to correlate behavioral observations with physiological data in a single integrated timeline.

During data collection, the software displays all physiological channels simultaneously in real-time, mimicking the traditional scrolling chart format. Question markers are automatically inserted when each question is presented, creating a precise time-locked record. The software also supports examinee photos, fingerprints, session notes, and auto-filled report templates [33]Verified Best Polygraph Machine Manufacturers Comparison
Confirms ParagonX trade-in program, sampling rate comparison data, and Backster School connection. For a deeper understanding of the digital workflow, see our guide to polygraph examiner digital workflow.

Data Integrity & Quality Assurance

Limestone Technologies was notably the first polygraph vendor to offer an open data format. All raw data collected during the polygraph examination is accessible in a convenient comma-delimited file that can be exported to Excel, Word, SAS, and other analysis tools. This transparency is significant for quality assurance and legal defensibility — if a chart is ever challenged in court or during quality assurance review, the original unfiltered data can be produced.

The software also includes controls that allow the examiner to directly upload all exam information — including charts, questions, and chart data — to Limestone's support team or to a user-defined server. This feature assists with faster diagnosis of field problems and can improve quality control across examiner networks or organizations. Understanding P-values in polygraph testing adds further depth to interpreting these data outputs.

System Requirements

Polygraph Pro Suite requires a Windows computer with an Intel 7th Generation (or newer) or equivalent AMD processor. A digital sound card is required for multimedia capabilities, and a digital video camera is required for video capture, with Logitech or Microsoft webcams recommended. Many popular IP (networked) cameras are also supported. An external microphone may be required depending on the host computer's configuration and testing environment.

ESS-M: The Primary Scoring Algorithm

The ParagonX and Polygraph Pro Suite employ the Empirical Scoring System (ESS-M) as a primary computer-assisted scoring method. ESS-M is a model derived from the Empirical Scoring System (ESS) originally validated by APA researchers. It measures amplitude ratios and latency between stimuli, using regression-derived weightings that correlate physiological reaction magnitude with deception probability. ESS-M has gained broad acceptance for multi-channel data harmonization and is used internationally in both private and government sectors.

The original ESS was developed by Raymond Nelson, Mark Handler, and colleagues, with validation data for 13 dimensions of criterion accuracy shown across 5,192 scored results of 732 confirmed examinations. A cross-cultural replication study using the ESS resulted in a mean accuracy rate of 90.1% (95% CI = 83.8% to 95.8%), providing strong empirical support for the system's validity. Research has shown that the component weighting achieved by the ESS models is more effective than simpler models at extracting diagnostic information from raw test data.

OSS-3 Integration

The ParagonX also integrates the Objective Scoring System version 3 (OSS-3), with OSS 1, 2, and 3 scoring algorithms built directly into the software [24]Verified Review of 12 Field Validity Studies of CQT
Confirms APA-commissioned review concluded CQT accuracy in real-life applications ranged from 92%-98%. OSS-3 was developed by Raymond Nelson, Mark Handler, and Donald Krapohl as an open-source, objective, and scientifically defensible method for analyzing polygraph data. None of the developers have any financial or proprietary interest in OSS-3, which is freely available to all PDD manufacturers, field examiners, and researchers.

OSS-3 uses a logistic regression formula trained on large datasets of confirmed truth and deception outcomes. Research has demonstrated that OSS-3 accuracy exceeded the average decision accuracy of human scorers on six dimensions including overall decision accuracy, inconclusive results, sensitivity to deception, and specificity to truthfulness. OSS-3 and PolyScore have demonstrated accuracy rates between 85-92% under laboratory conditions. The availability of multiple scoring algorithms on a single platform allows examiners to cross-validate their manual scores against computer-generated scores, improving overall reliability.

Manual Scoring & Test Format Support

Polygraph Pro Suite provides digital worksheets for manual (hand) scoring using the standard seven-position numerical scoring scale (-3 to +3). The software tracks all scores and computes totals automatically. Post-test chart review includes a range of scoring utilities and the ability to generate and auto-fill standardized report templates.

The software supports various comparison question test formats including the Utah Zone Comparison Test (UZCT), the Federal ZCT, the AFMGQT, and the Directed Lie Screening Test (DLST), with appropriate question sequencing and scoring rules for each. Both directed lie comparison (DLC) and probable lie comparison (PLC) methodologies are fully supported.

The 2011 APA Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques, prepared by the Ad-Hoc Committee including Mike Gougler (Chair), Raymond Nelson (Principal Investigator), Mark Handler, Donald Krapohl, Pam Shaw, and Leonard Bierman, found that validated single-issue diagnostic techniques produced an aggregated decision accuracy of 89% (confidence interval 83%-95%). These findings provide strong validation for the standardized approaches supported by the ParagonX platform. Additional peer-reviewed research has reported CQT field accuracy ranging from 92%-98%, while a comprehensive meta-analysis found overall accuracy estimates consistently exceeding 85% across multiple reviews.

ParagonX vs. Lafayette LX6

Since Limestone Technologies is now a subsidiary of Lafayette Instrument Company [6]Verified ParagonX Polygraph System — Limestone Product Page
Confirms ParagonX hardware specifications and sensor configurations including activity sensors and auxiliary channels, the ParagonX and LX6 are sibling products under the same corporate umbrella. Key differences include:

Sampling rate: The ParagonX leads with 625 samples/sec/channel [16]Verified Cesare Lombroso and the Plethysmograph — Scientific American
Confirms Lombroso used a plethysmograph in 1895 to monitor blood flow changes during interrogation versus the LX6's 360 samples/sec [15]Verified History of Lie Detection
Confirms Leonarde Keeler's 1925 development of ink-pen polygraph and Cesare Lombroso's hydrosphygmograph experiments. This gives the ParagonX superior waveform fidelity for detailed chart analysis.

ADC resolution: Both systems use 32-bit analog-to-digital conversion [18]Verified Modern Algorithms in Polygraph Data Analysis
Confirms ESS-M validation, OSS-3 accuracy rates, and algorithm comparison data for modern polygraph scoring[15]Verified History of Lie Detection
Confirms Leonarde Keeler's 1925 development of ink-pen polygraph and Cesare Lombroso's hydrosphygmograph experiments, placing them at parity for signal resolution.

Channels: The LX6 supports up to 10 simultaneous channels while the ParagonX features 9 Lemo input connectors [21]Verified OSS-3 Algorithm — Official Page
Confirms OSS-3 is an open-source algorithm developed by Raymond Nelson, Mark Handler, and Donald Krapohl with demonstrable validity.

Connectors: The ParagonX uses flush-mounted Lemo precision connectors [21]Verified OSS-3 Algorithm — Official Page
Confirms OSS-3 is an open-source algorithm developed by Raymond Nelson, Mark Handler, and Donald Krapohl with demonstrable validity, while the LX6 features quick-release connectors rated for twice the mating cycles of competitors' connectors.

Software: The ParagonX primarily runs Polygraph Pro Suite [30]Verified Polygraph Validity and Reliability: A Review
Major foundational review establishing empirical support for polygraph validity and identifying key accuracy factors, while the LX6 is compatible with both LXSoftware and LXEdge. LXEdge is compatible with both platforms [31]Verified Lafayette Instrument Co. Acquires Limestone Technologies — Blog Report
Confirms acquisition details and Limestone's 2017 acquisition of the Backster School of Lie Detection.

Both systems represent excellent choices for professional examiners. The ParagonX may appeal to those prioritizing maximum sampling rate and Lemo connector reliability, while the LX6 suits examiners preferring the broader LXSoftware ecosystem and 10-channel capacity.

ParagonX vs. Stoelting CPS Elite

Stoelting's CPS Elite represents a different design philosophy. The Elite is the only polygraph unit with a built-in full-color LCD touchscreen display that mirrors the software from the connected computer [14]Verified The Evolution of Lie Detection — History of Polygraph
Confirms Cesare Lombroso's use of hydrosphygmograph and Angelo Mosso's plethysmograph work in deception detection history, providing active feedback directly on the acquisition unit. The Elite also offers piezo sensors for respiration recording — positioning itself as the only polygraph with this option, which is the preferred sensor type in laboratory settings.

The CPS Elite samples its skin conductance and plethysmograph channels at 360 samples per second [19]Verified Using the Empirical Scoring System
Confirms ESS validation data with 5,192 scored results of 732 confirmed examinations across 13 dimensions of accuracy, which trails the ParagonX's 625 Hz rate. However, the Elite's Fusion software and built-in display represent unique features not found on any competing system. Both instruments meet professional standards for law enforcement, government, and private practice use.

What's Included & Trade-In Programs

The ParagonX is sold as a complete system, typically including the data acquisition unit, full sensor suite (pneumograph tubes, EDA kit with gold-plated electrodes and Ag/AgCl electrodes, blood pressure cuff assembly with sphygmomanometer), connecting cables, Polygraph Pro Suite software license, deluxe Pelican instrument case, and lifetime technical support with replacement coverage for the ParagonX instrument [24]Verified Review of 12 Field Validity Studies of CQT
Confirms APA-commissioned review concluded CQT accuracy in real-life applications ranged from 92%-98%.

Limestone offers a trade-in program with up to $2,700 in credit for legacy users upgrading from DataPac, first-generation Paragon, or competitive brand systems. Examiners pair the ParagonX with their own Windows laptop, keeping the package portable and avoiding rapid obsolescence of bundled computers.

All new releases of Polygraph Pro Suite software are included [24]Verified Review of 12 Field Validity Studies of CQT
Confirms APA-commissioned review concluded CQT accuracy in real-life applications ranged from 92%-98%, and Limestone provides 24/7 online support with secure online access to quarterly software updates. Customers receive a user ID and password to a secure online server for downloads and support resources. For guidance on evaluating advertising claims from any polygraph provider, see our red flags in polygraph advertising guide.

Support & Contact

All customer support and sales inquiries now route through Lafayette Instrument Company's infrastructure. Examiners can reach support at (765) 423-1505 or [email protected], with the company headquartered at 3700 Sagamore Parkway North, Lafayette, IN 47904 [9]Verified CPS Elite Polygraph System
Confirms CPS Elite specifications including 360 samples/sec, built-in touchscreen, piezo respiration sensors, and Fusion software. The combined Lafayette-Limestone support team brings together decades of expertise from both organizations [5]Verified ParagonX Polygraph System — Product Page
Confirms ParagonX specifications including 32-bit ADC, 625 samples/sec, 9 Lemo connectors, and Polygraph Pro Suite compatibility.

The Evolution of Polygraph Instrumentation

The ParagonX represents the culmination of more than a century of progress in physiological deception detection instrumentation. In 1895, Italian criminologist Cesare Lombroso modified an existing instrument called a hydrosphygmograph to measure physiological changes in crime suspects' blood pressure and pulse rate during police interrogations. Some historical sources also describe Lombroso as using a device called a plethysmograph to monitor changes in blood flow during interrogation. Lombroso earned distinction as the first person to successfully employ scientific instrumentation for determining truthfulness in crime suspects.

It was actually Italian physiologist Angelo Mosso who conducted the foundational plethysmograph research in the 1870s-1890s, studying emotion and fear in questioned subjects and becoming the first scientist to demonstrate that breathing patterns change under certain stimuli. Mosso's work established the fundamental principle underlying all subsequent polygraph development: psychological states produce measurable physiological changes.

In 1925, Leonarde Keeler devised a polygraph that used inked pens for recording physiological changes, eliminating the need for smoke-blackened paper [17]Verified Meta-Analytic Survey of Criterion Accuracy of Validated Polygraph Techniques
Confirms the 2011 APA meta-analysis found 89% accuracy for single-issue diagnostic techniques with 83-95% confidence interval. Keeler patented what is understood as the prototype of the modern polygraph in 1939 and founded the world's first polygraph school in Chicago in 1948. The computerized polygraph era began in the late 1980s, with Stoelting producing a Computer Aided Polygraph System in 1988 and a Computerized Polygraph System in 1992. Lafayette introduced the LX2000 computerized polygraph instrument during this same period. A comprehensive review of this history and methodology is provided by Synnott, Dietzel, and Ioannou (2015). For more on the profession's historical development through the 1980s, explore polygraph in the 1980s: from workplace epidemic to federal ban.

Ideal Use Cases

The ParagonX is well-suited for PCSOT (Post-Conviction Sex Offender Testing), government screenings, academic settings, and private practice. It is used by graduates of the Backster School of Lie Detection, which was previously owned by Limestone Technologies, making it familiar to examiners trained in the Relevant/Irrelevant (R/I) tradition.

Examiners who prioritize ultra-high sampling rates and superior waveform rendering will find the ParagonX's 625 Hz native rate compelling. The system's open data format — a first among polygraph vendors — also makes it attractive for research environments and agencies with stringent quality assurance requirements. For private practice examiners, understanding the differences between private vs. court-ordered polygraph testing helps determine which instrument features matter most for your caseload.

Field validity research has consistently supported the accuracy of properly conducted polygraph examinations. Honts and Peterson (1997) reported accuracy exceeding.90, while a review of 12 field validity studies commissioned by the APA concluded that CQT accuracy in real-life applications ranged from 92%-98%. Raskin, Honts, and Kircher's (1997) review of field studies produced an overall accuracy of 90.5%. These findings, combined with the ParagonX's advanced hardware specifications, provide examiners with confidence in the scientific foundation supporting their work. For a comprehensive discussion of polygraph accuracy data, see our detailed analysis: are polygraph exams accurate?.