7.2 CAD Interfaces: Mobile Data, RMS & External Telematics

7.2 CAD Interfaces: Mobile Data, RMS & External Telematics

Quick Answer: Modern Computer Aided Dispatch (CAD) systems function as centralized systems integrators, communicating continuously with field units, permanent record repositories, adjacent public safety agencies, and commercial telematics providers. Field connectivity is anchored by Mobile Data Terminals (MDTs) communicating over high-priority wireless bearer networks—principally FirstNet (Band 14 LTE/5G) utilizing Quality of Service, Priority, and Preemption (QPP) with mission-critical QoS Class Identifiers (QCI 65, 69, and 70). The transient operational record captured by CAD during an active response is handed off to Records Management Systems (RMS) compliant with national reporting standards: FBI NIBRS for law enforcement, NFIRS and cloud-native NERIS for fire services, and NEMSIS v3 for emergency medical care. Cross-jurisdictional CAD-to-CAD exchange relies on the APCO/NENA Emergency Incident Data Document (EIDD) standard and NENA's Emergency Incident Data Object (EIDO) standards, informed by the National Information Exchange Model (NIEM). External Advanced Automatic Collision Notification (AACN) systems stream real-time crash kinematics (delta-V, Principal Direction of Force [PDOF], rollover metrics) directly into CAD intake queues via telematics service providers, NG9-1-1 additional data, and modern data clearinghouses.

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1. Mobile Data Terminals (MDT/MDC) & In-Vehicle Telemetry

Field responders interact with CAD primarily through Mobile Data Terminals (MDTs) or Mobile Data Computers (MDCs)—ruggedized vehicular laptop computers or detachable tactical tablets permanently mounted in police cruisers, fire apparatus, and ambulances.

                             FIELD TELEMETRY WORKFLOW

  [In-Vehicle MDT / MDC Client] ◄─── FirstNet Band 14 / LTE / P25 ───► [CAD Mobile Gateway]
    • Silent Status Function Keys                                         │
    • Live Narrative Streaming                                           ▼
    • Touchscreen Tactical Mapping                                 [CORE CAD ENGINE]
    • Silent Panic Duress Switch                                          │
               │                                                          ▼
               ▼                                            [Dispatcher Console Queues]
  [Vehicle Telemetry Unit]
   • Multi-GNSS / GPS Receiver (1-5 Hz)
   • Dead Reckoning / Inertial Gyroscopes
   • OBD-II / J1939 Engine Bus Telemetry

In-Vehicle Hardware & Ergonomic Standards

In-vehicle computing environments present extreme physical challenges: thermal shock, intense vibration, direct sunlight glare, and electrical power surges. Public safety mobile hardware adheres to stringent military and industrial baselines:

• MIL-STD-810H & IP Ratings: Ruggedized against physical impact, ballistic shock, continuous vehicle vibration, moisture, and dust ingress (minimum IP65 or IP67 ratings).
• Display Ergonomics & Night Mode: High-nit daylight-readable screens (minimum 1,000 to 1,200 nits) equipped with one-touch black-and-red night vision modes to preserve the responder's physiological dark adaptation during nighttime operations.
• Crash-Tested Vehicular Docking: Crash-rated vehicle mounts conforming to SAE J3043 standards, ensuring that heavy computing terminals do not detach and become lethal projectile hazards during high-speed vehicular collisions or rollovers.

Core MDT Functional Capabilities

1. Silent Status Updates: Responders manipulate physical or onscreen hotkeys to transition their operational status (EN_ROUTE, ON_SCENE, STAGED, AVAILABLE_RADIO, RETURNING_TO_QUARTERS). These updates instantly refresh CAD maps and dispatcher console queues without consuming congested voice radio airtime.
2. CAD Incident Remarks Streaming: Field units observe real-time narrative entries typed by telecommunicators, including updates from secondary callers, premise history hazard alerts (e.g., hazardous materials, violent occupants, guard dogs), and structural building schematics.
3. Silent Duress / Emergency Panic Alarm: A dedicated hardware button or high-contrast onscreen control that immediately transmits an emergency distress beacon to CAD. The system sounds audible alarms across the communications center, flashes the unit's map icon in red, locks the terminal's GPS polling rate to continuous tracking, and can trigger in-cab microphone hot-mic voice transmission over the radio.

Automatic Vehicle Location (AVL) & Dead Reckoning

Effective CAD operations depend on real-time Automatic Vehicle Location (AVL) tracking:

• GNSS/GPS Telemetry: Multi-constellation satellite receivers (GPS, GLONASS, Galileo) generate location fixes at 1 to 5 Hz intervals.
• Transmission Thresholds: To balance network bandwidth with tracking accuracy, AVL transmissions to CAD are governed by configurable business rules: periodic time deltas (e.g., every 5 seconds when emergent, every 30 seconds when idle), distance traveled deltas (e.g., every 100 meters), or heading turn deltas (e.g., whenever the vehicle executes a turn greater than 30 degrees).
• Dead Reckoning & Inertial Sensors: In dense "urban canyons" surrounded by skyscrapers, under subterranean roadway decks, or inside multi-level parking garages, satellite signals suffer from multipath distortion or complete blockage. Advanced vehicle telemetry gateways employ Dead Reckoning (DR) modules combining vehicle speedometer pulses (via the OBD-II or J1939 CAN bus) with internal 3-axis gyroscopes and accelerometers. The system mathematically tracks vehicle position from the last known satellite fix with high precision until satellite visibility is re-established.

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2. Public Safety Wireless Bearer Networks

Field computing requires continuous, highly survivable wireless data connectivity. Public safety agencies engineer multi-bearer transport networks to ensure communications survive commercial network outages.

                 PUBLIC SAFETY WIRELESS BEARER HIERARCHY

       [FIRSTNET: BAND 14 LTE/5G] ────► Primary Bearer: Dedicated 700 MHz Spectrum
       (QPP Priority & Preemption)      QCI 65 (MC PTT) / 69 (MC Signaling) / 70 (MC Data)
                    │ (Automatic Failover)
                    ▼
       [COMMERCIAL LTE / 5G CARRIERS] ─► Secondary Bearer: Commercial Dual-SIM Routers
       (Multi-Carrier Roaming)          High Bandwidth, Subject to Commercial Congestion
                    │ (Automatic Failover)
                    ▼
       [PRIVATE P25 DIGITAL DATA] ────► Tertiary Fallback: Private 700/800 MHz LMR
       (Conventional / Trunked Data)    Low Bandwidth (about 9.6 kbps), High Survivability
                    │ (Local Offload)
                    ▼
       [STATION SECURE WI-FI] ────────► Bulk Synchronization: Mapping Cache Updates,
       (Broadband In-Quarters)          Video Offload, Firmware Patches

FirstNet & Quality of Service, Priority, and Preemption (QPP)

Created under the Middle Class Tax Relief and Job Creation Act of 2012, FirstNet represents the nationwide public safety broadband network operating in the dedicated 700 MHz Band 14 spectrum:

• Quality of Service, Priority, and Preemption (QPP): During major emergencies, commercial cellular towers become severely congested as thousands of civilians simultaneously place calls and upload video, blocking data transmission. FirstNet implements automated QPP at the physical radio access network (RAN) and evolved packet core (EPC) layers:
  • Priority: Public safety packets are tagged for immediate transmission ahead of any commercial traffic.
  • Preemption: If an LTE/5G cell tower reaches 100% capacity, FirstNet networks automatically preempt (drop or reallocate bandwidth away from) civilian commercial users to ensure first responder data, CAD messages, and video streams connect without delay.
• QoS Class Identifiers (QCI): FirstNet enforces 3GPP Quality of Service standards: QCI 65 (mission-critical push-to-talk voice), QCI 69 (mission-critical delay-sensitive signaling), and QCI 70 (mission-critical data, such as CAD traffic).

Redundant Multi-Bearer Router Architectures

Modern public safety vehicles deploy intelligent multi-network vehicle routers (e.g., Cradlepoint, Sierra Wireless) configured with active dual-SIM or tri-SIM modems. The router constantly monitors Received Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and round-trip packet latency. If the primary FirstNet connection drops, the router automatically fails over to a secondary commercial carrier within milliseconds.

Private Land Mobile Radio (LMR) Packet Data Fallback

When commercial and cellular broadband networks collapse entirely (e.g., following a severe hurricane or catastrophic cyberattack), public safety vehicle routers fall back to private Project 25 (P25) digital packet data channels operating across agency-owned 700/800 MHz infrastructure. While limited in bandwidth (roughly 9.6 kbps on a P25 data channel), P25 packet data reliably transmits basic CAD text dispatches, silent unit status updates, and emergency panic alerts over vast geographic distances.

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3. Records Management Systems (RMS) Integration & National Standards

A fundamental architectural principle tested on the ENP examination is the strict operational division between CAD and RMS.

┌────────────────────────────────────────┐     ┌────────────────────────────────────────┐
│      COMPUTER AIDED DISPATCH (CAD)     │     │    RECORDS MANAGEMENT SYSTEM (RMS)     │
├────────────────────────────────────────┤     ├────────────────────────────────────────┤
│ • Manages TRANSIENT, real-time events  │     │ • Manages PERMANENT historical records │
│ • Millisecond-to-second operational    │     │ • Long-term legal & administrative     │
│   response window                      │   ──►   archive                              │
│ • Incident intake, geocoding, unit     │     │ • Master indices (Person, Vehicle, MVA)│
│   tracking, active field dispatch      │     │ • Regulatory compliance (NIBRS,        │
│ • Data purged or archived post-event   │     │   NERIS, NEMSIS)                       │
└────────────────────────────────────────┘     └────────────────────────────────────────┘

The CAD-to-RMS Integration Pipeline

During an active incident, CAD records high-precision timestamps (call created, dispatched, en route, on scene, cleared), unit rosters, and telecommunicator narrative notes. Upon incident closure, CAD executes an automated Extract, Transform, Load (ETL) routine over secure web services (RESTful APIs or SOAP XML), pushing the complete operational record into the Records Management System (RMS).

Discipline-Specific RMS Standards

1. Law Enforcement RMS:
   • Serves as the master repository for case investigations, criminal arrest reports, warrants, property and evidence tracking, and booking photos.
   • FBI NIBRS Compliance: All law enforcement RMS suites must comply with the FBI's National Incident-Based Reporting System (NIBRS). Unlike the legacy Uniform Crime Reporting (UCR) Summary System—which recorded only the single most severe offense in an incident (the Hierarchy Rule)—NIBRS captures comprehensive incident-level data on up to 10 distinct criminal offenses per incident, detailing victim-offender relationships, weapon usage, and demographic data.
2. Fire RMS:
   • Captures structural fire investigations, apparatus run logs, hydrant maintenance records, and commercial building code inspection compliance.
   • NFIRS to NERIS Migration: Historically governed by the National Fire Incident Reporting System (NFIRS) managed by the U.S. Fire Administration (USFA). The fire service is actively migrating to the modern, cloud-native National Emergency Response Information System (NERIS). NERIS provides real-time geospatial data ingestion, native integration with CAD dispatch feeds, and advanced risk analytics.
3. EMS RMS & Electronic Patient Care Reports (ePCR):
   • Documents patient clinical assessments, vital signs, medication administrations, airway interventions, and billing documentation.
   • NEMSIS v3 Compliance: Must comply with the National Emergency Medical Services Information System (NEMSIS v3) standard. NEMSIS establishes universal clinical data elements, programmatically binding CAD dispatch timestamps (PSAP call answer, unit dispatch, wheel-turn en route, arrival on scene, patient contact, transport departure, hospital arrival) directly to medical treatment logs. This end-to-end linkage supports clinical quality improvement, state EMS data reporting, and national EMS research.

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4. Inter-System Standards: NIEM, GJXDM & CAD-to-CAD Interoperability

In complex metropolitan areas, an incident frequently spans multiple neighboring jurisdictions. A multi-vehicle crash on a county boundary may require police from City A, fire rescue from City B, and a private ambulance contracted by County C. Historically, telecommunicators were forced to pick up administrative telephone lines to manually read notes aloud to neighboring dispatchers, introducing fatal communication delays.

                     CAD-TO-CAD INCIDENT DATA EXCHANGE

  [Agency A CAD System]                                   [Agency B CAD System]
  ┌───────────────────┐                                   ┌───────────────────┐
  │ CAD Core Engine   │                                   │ CAD Core Engine   │
  └─────────┬─────────┘                                   └─────────┬─────────┘
            │                                                       │
  ┌─────────┴─────────┐                                   ┌─────────┴─────────┐
  │ CAD2CAD Broker    │ ◄─── Secure HTTPS / TLS 1.3 ─────►│ CAD2CAD Broker    │
  └───────────────────┘      [APCO/NENA EIDD 2.105.1]      └───────────────────┘
                             [EIDD (NIEM) / EIDO JSON]
                             • Incident Creation & Handoff
                             • Bi-Directional Narrative Updates
                             • Real-Time Mutual Aid AVL Push
                             • Resource Request / Accept / Deny

The National Information Exchange Model (NIEM)

Disparate CAD vendors historically used conflicting, proprietary database schemas. Agency A might categorize an incident as MVA_INJURY with priority 1, while Agency B categorizes it as 10-50_PI with priority RED. Connecting them directly produced severe semantic confusion.

To resolve this, the public safety community adopted the National Information Exchange Model (NIEM)—which evolved from the earlier Global Justice XML Data Model (GJXDM):

• NIEM Domains: NIEM establishes a universal, standardized public safety data dictionary and common XML/JSON schema definitions, particularly within the Emergency Management and Justice domains.
• Information Exchange Package Documentation (IEPD): Standardized schema contracts that define exactly how data elements (incident location, caller identity, unit status, event nature) must be formatted and validated during cross-system exchanges.

EIDD and EIDO: Standard Incident Data Exchange

The APCO/NENA 2.105.1-2017 Emergency Incident Data Document (EIDD) standard defines a vendor-neutral, NIEM-conformant way to describe an incident and its updates. NENA carries the same concept into NG9-1-1 as the Emergency Incident Data Object (EIDO, NENA-STA-021), a JSON object, with conveyance between systems defined in NENA-STA-024. Related APCO standards supply common vocabularies, such as APCO ANS 2.103.2 common incident types. Together they support:

1. Incident Creation / Transfer: Pushes a complete incident record from Agency A to Agency B, instantly generating an active incident in Agency B's pending queue without human telephone interaction.
2. Continuous Narrative Synchronization: When telecommunicator A enters updated caller remarks ("Driver is trapped and unconscious"), the CAD2CAD broker immediately updates telecommunicator B's incident remarks field.
3. Cross-Agency AVL & Unit Status: Permits Agency A to visualize the real-time position and operational availability of Agency B's mutual aid units on their own dispatch mapping console.
4. Mutual Aid Resource Request / Response: Enables automated electronic resource requests (e.g., requesting 2 structural engines and 1 ladder) accompanied by automated acceptance, modification, or rejection workflows.

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5. External Telematics: AACN, Crash Detection & Third-Party Platforms

Modern motor vehicles and consumer mobile devices have evolved into intelligent sensor platforms capable of reporting collisions and medical emergencies automatically.

                       TELEMATICS DATA FLOW PIPELINE

  [Vehicle Collision Occurs]
   • Deceleration Sensors (delta-V)
   • Impact Gyroscopes (PDOF & Rollover)
   • Seatbelt Buckle Sensors & Airbag Deployments
              │
              ▼
  [Telematics Service Provider (TSP): OnStar, SiriusXM, OEM]
              │
              ├───────────────────────────────┬───────────────────────────────┐
              ▼  (Direct In-Band Voice Call)  ▼  (Out-of-Band Data Push)      ▼  (Data Clearinghouse)
  [Voice Path to 9-1-1 PSAP]     [NG9-1-1 Additional Data]       [RapidSOS / Direct CAD API]
   • Telematics Specialist        • High-Precision Coordinates  • Crash Kinematics Payload
   • Establishes 3-way call       • Raw Crash Telemetry (delta-V)• CDC Urgency Algorithm (%)
   • Voice verification           • Occupant Count & Airbags    • Populates CAD Incident Form

Advanced Automatic Collision Notification (AACN) Mechanics

Commercial vehicle systems (such as GM OnStar, BMW Assist, Mercedes-Benz mbrace, SiriusXM Connected Vehicle) incorporate Advanced Automatic Collision Notification (AACN). Telematics data reaches PSAPs through the telematics service provider (voice relay plus data), NG9-1-1 additional data for vehicle-initiated calls (IETF RFC 8148), and clearinghouse integrations. Key data elements include:

• Delta-V ($\Delta V$): Measures the sudden change in vehicle velocity (in miles per hour or kilometers per hour) resulting from the impact. A delta-V exceeding $20\text{ to }25\text{ mph}$ indicates high kinetic energy transfer and severe occupant deceleration trauma.
• Principal Direction of Force (PDOF): The vector angle of the primary impact expressed in degrees (or clock positions, e.g., 12 o'clock for direct frontal, 3 o'clock for passenger side-impact T-bone). Side-impact collisions correlate with significantly higher rates of thoracic and pelvic trauma due to minimal vehicle crumple zones.
• Rollover Sensor Telemetry: Detects angular roll rate and orientation, identifying whether the vehicle overturned and the estimated number of quarter-turns.
• Seatbelt Status & Occupant Count: Identifies which passenger seats were occupied and whether seatbelt pre-tensioners latched at the moment of impact.

The CDC / ACS Field Triage Protocol & The Urgency Algorithm

AACN systems pass crash telemetry through clinical injury prediction models—specifically the CDC/American College of Surgeons Field Triage Decision Scheme and specialized predictive algorithms (such as the Urgency algorithm):

• The algorithm computes the statistical probability that an occupant has sustained an Injury Severity Score (ISS) $\ge 15$ (severe, life-threatening internal trauma).
• If the probability exceeds 20%, CAD flags the incident as high-acuity, prompting telecommunicators to proactively dispatch Advanced Life Support (ALS) rescue squads, alert regional Level 1 trauma centers, and place aeromedical evacuation helicopters on standby before the first ground unit arrives on scene.

Consumer Smartphone Crash & Fall Detection

Contemporary smartphones (e.g., Apple iPhone Crash Detection, Google Android Personal Safety) and wearable smartwatches utilize built-in 3-axis high-g accelerometers, gyroscopes, barometric pressure sensors, and microphone acoustic signatures (detecting airbag deployment sounds and breaking glass) to detect vehicular crashes or hard falls:

• Third-Party Data Clearinghouses (e.g., RapidSOS, Emergency Data Exchange): Rather than relying on slow voice-relay operators, modern smartphone telematics push structured JSON data payloads into CAD intake screens via secure cloud APIs.
• Verification Protocols: False positives (e.g., a phone dropped while riding a roller coaster or skiing) present operational challenges. Public safety protocol mandates attempting immediate voice callbacks, challenging open lines, and reviewing secondary sensor data before clearing unconfirmed automated crash alerts.

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6. Operational Traps & ENP Exam Watch

• CAD vs. RMS Functional Boundary: CAD is designed for transient, real-time dispatch and resource tracking during active incidents. RMS is the permanent legal, administrative, and clinical data repository.
• FirstNet QPP Operation: FirstNet Band 14 guarantees Quality of Service, Priority, and Preemption (QPP). Preemption actively drops or throttles commercial traffic to preserve bandwidth for public safety during localized cellular network saturation.
• NIEM Public Safety Role: NIEM (built upon legacy GJXDM) is the national semantic standard that enables heterogeneous CAD systems to exchange incident records and unit statuses without vendor data incompatibility.
• AACN Telematics Trauma Triage: Delta-V measures velocity change; PDOF measures impact direction. High delta-V combined with lateral PDOF indicates severe internal occupant injury, justifying proactive trauma center and aeromedical dispatch under CDC field triage protocols.
• NIBRS vs. UCR Reporting: Law enforcement RMS compliance requires FBI NIBRS, which abandons the old UCR "Hierarchy Rule" and captures detailed information on up to 10 offenses per incident.