All About Sim800l Gsm Module: Specifications, Performance, and Common Uses

Types of SIM800L GSM Modules

The SIM800L GSM module is a compact, cost-effective, and widely adopted solution for wireless communication in embedded systems and IoT (Internet of Things) applications. Known for its reliability and low power consumption, this module supports GSM/GPRS connectivity across multiple frequency bands, enabling global compatibility. It is commonly used in remote monitoring, home automation, vehicle tracking, and data transmission projects. Available in various configurations, each variant of the SIM800L is optimized for specific use cases, from basic SMS control to advanced GPS-enabled tracking and industrial-grade durability.

Basic SIM800L GSM Module

The standard version ideal for entry-level and general-purpose applications requiring voice, SMS, and data connectivity.

Advantages

• Supports quad-band frequencies (850/900/1800/1900 MHz) for global coverage
• Operates on a wide voltage range (3.4V–4.4V), compatible with most power supplies
• Enables SMS, voice calls, and GPRS data transmission
• Compact size and low cost make it ideal for DIY and hobbyist projects
• Easy integration with microcontrollers like Arduino and Raspberry Pi

Limitations

• No built-in GPS or advanced power-saving features
• Requires external components (e.g., antenna, SIM holder, power regulator)
• Potential signal instability without proper decoupling capacitors

Best for: Home automation, simple telemetry, remote alerts, and educational projects

SIM800L with GPS Integration

A dual-function module combining GSM/GPRS communication with real-time GPS location tracking.

Advantages

• Provides accurate real-time geolocation via GPS (often with support for GLONASS)
• Enables location-based services such as fleet tracking, asset monitoring, and personal safety devices
• Supports SMS and data transmission with location embedded in messages
• Highly useful for logistics, delivery systems, and wearable tracking devices
• Reduces need for separate GPS modules, saving space and complexity

Limitations

• Higher power consumption due to dual functionality
• More expensive than the basic module
• Requires clear sky view for optimal GPS signal acquisition

Best for: Vehicle trackers, pet/child locators, drone telemetry, and field monitoring systems

Low-Power SIM800L Module

Optimized for battery-powered and energy-sensitive applications with enhanced sleep and idle modes.

Advantages

• Ultra-low power consumption: ~20mA in idle mode, ~100mA during transmission
• Supports deep sleep and power-down modes to extend battery life
• Ideal for remote sensors, solar-powered systems, and portable devices
• Can operate for weeks or months on a single charge with proper power management
• Includes automatic power-saving protocols

Limitations

• Slightly reduced signal sensitivity in low-power modes
• May require additional firmware configuration for optimal power savings
• Limited availability compared to standard versions

Best for: Wireless sensors, environmental monitors, smart agriculture, and off-grid IoT devices

High-Temperature SIM800L Module

Engineered for durability in extreme environments with enhanced thermal and environmental resistance.

Advantages

• Built with industrial-grade components to withstand temperatures up to 85°C or higher
• Resistant to dust, moisture, and vibration, suitable for harsh conditions
• Ideal for automotive under-hood installations, industrial machinery, and outdoor enclosures
• Longer lifespan in demanding applications compared to consumer-grade modules
• Improved circuit protection and thermal management

Limitations

• Higher cost due to ruggedized design
• Larger footprint in some variants
• May require additional heat dissipation in enclosed spaces

Best for: Automotive systems, industrial automation, oil & gas monitoring, and outdoor infrastructure

Development Board with SIM800L

A ready-to-use platform integrating the SIM800L with supporting circuitry for rapid prototyping and testing.

Advantages

• Includes onboard voltage regulation, SIM card slot, antenna connector, and status LEDs
• Plug-and-play design reduces wiring errors and speeds up development
• Compatible with common microcontrollers and IDEs (Arduino, ESP32, etc.)
• Great for beginners, educators, and engineers validating concepts quickly
• Often includes UART-to-USB converter for direct PC communication

Limitations

• Larger size compared to bare modules
• Less suitable for space-constrained final products
• May include unnecessary components, increasing cost for production use

Best for: Prototyping, classroom projects, proof-of-concept testing, and product development

Module Type	Key Features	Power Efficiency	Best Use Case	Integration Level
Basic SIM800L	GSM/GPRS, SMS, voice, quad-band	Medium	Simple IoT, home automation	Intermediate (requires external components)
SIM800L + GPS	Location tracking, real-time data	Medium-Low	Fleet management, wearables	High (integrated solution)
Low-Power SIM800L	Deep sleep modes, energy saving	Excellent	Battery-powered sensors	Intermediate
High-Temp SIM800L	Heat/dust resistant, rugged design	Medium	Industrial/automotive systems	Intermediate to High
Development Board	Pre-wired, USB interface, LEDs	Medium	Rapid prototyping	High (plug-and-play)

Expert Tip: When using any SIM800L variant, ensure a stable 4V power supply with sufficient current (up to 2A peak during transmission). Use a high-quality LDO or DC-DC converter with adequate filtering capacitors to avoid reset issues caused by voltage drops.

Material & Durability of SIM800L GSM Module

The durability and long-term reliability of the SIM800L GSM module are heavily influenced by the materials used in its construction. As a widely used component in IoT, remote monitoring, and communication systems, its resilience under various environmental conditions is crucial. This guide explores the key materials used in the module’s design and how they contribute to its performance and lifespan.

PCB (Printed Circuit Board) Material

The foundation of the SIM800L module is typically built on an FR-4 grade fiberglass-reinforced epoxy laminate, the most common material for PCBs due to its excellent electrical insulation, mechanical strength, and thermal stability. FR-4 provides reliable performance under standard operating conditions and resists moisture absorption and mechanical warping.

In higher-performance or industrial-grade variants, some manufacturers incorporate aluminum-backed PCBs or metal-core boards to improve heat dissipation. This is particularly beneficial in enclosed spaces or high-temperature environments where thermal management is critical. Enhanced thermal conductivity helps prevent overheating of the GSM chipset, thereby extending the module’s operational life and maintaining signal integrity.

Metal Casing & Environmental Protection

The SIM800L module is commonly enclosed in a precision-engineered metal casing that serves dual purposes: electromagnetic shielding and physical protection. The metal enclosure acts as a Faraday cage, minimizing interference from external RF sources and preventing signal leakage—critical for stable GSM communication.

Beyond EMI protection, the casing shields internal components from dust, moisture, and mechanical impact. For outdoor or industrial deployments, advanced versions feature IP-rated enclosures (e.g., IP67) with rubber gaskets or conformal coatings. These protective measures ensure resistance to water ingress, humidity, and corrosive atmospheres, making the module suitable for applications in agriculture, automotive systems, and remote telemetry.

Connectors & Signal Integrity

The module’s connectors—whether pin headers or solder pads—are typically gold-plated to ensure low contact resistance and excellent corrosion resistance. Gold plating prevents oxidation over time, maintaining reliable electrical connections even in humid environments.

For antenna interfaces, connectors are often made from brass or copper alloys, materials chosen for their high conductivity and mechanical durability. These metals support strong RF signal transmission and resist wear from repeated mating cycles. Proper connector design ensures minimal signal loss and long-term stability, especially in mobile or vibration-prone installations.

Soldered Components & Assembly Quality

Passive components such as resistors, capacitors, and inductors are surface-mounted using lead-free solder in compliance with RoHS standards. This solder offers strong metallurgical bonds and good resistance to thermal cycling, reducing the risk of joint fatigue and cracking under temperature fluctuations.

High-quality reflow soldering techniques ensure consistent joint formation, minimizing defects like cold solder joints or bridging. The use of temperature-stable ceramic capacitors and precision resistors further enhances the module’s reliability across varying operating conditions.

Antenna Design & Material Choice

The SIM800L supports both internal and external antennas, each designed with durability in mind. Internal antennas are typically etched from flexible copper or printed directly onto the PCB, allowing integration into compact devices while maintaining resilience to repeated flexing.

External antennas, used in applications requiring extended range or better signal penetration, are constructed from robust materials such as stainless steel radiators encased in UV-resistant PVC or rubber sheathing. These materials provide excellent weather resistance, ensuring reliable performance in outdoor environments exposed to rain, sunlight, and extreme temperatures.

Thermal Performance & Heat Resistance

The SIM800L’s core components, including the GSM chipset and power management ICs, are designed to operate reliably at temperatures up to 85°C and can withstand brief exposure to over 100°C during transmission peaks. The combination of thermally efficient PCB materials, proper layout design, and optional heat-dissipating casings allows the module to function in demanding environments such as engine compartments, outdoor enclosures, or direct sunlight.

To maximize thermal resilience, users are advised to ensure adequate ventilation, avoid enclosing the module in sealed plastic housings without heat vents, and consider using thermal pads or heatsinks in continuous transmission scenarios.

Component	Material Used	Function & Durability Benefit
PCB Base	FR-4 Epoxy / Aluminum Core	Provides structural stability, electrical insulation, and enhanced heat dissipation in upgraded models
Enclosure	Galvanized Steel or Alloy	EMI shielding, mechanical protection, and environmental resistance
Connectors	Gold-plated Copper, Brass Alloys	Ensures low resistance, corrosion resistance, and durable electrical contact
Antenna (External)	Stainless Steel + UV-resistant PVC	Durable in outdoor conditions, resistant to weathering and UV degradation
Solder Joints	Lead-Free Solder (SAC Alloy)	RosH-compliant, thermally stable, and resistant to mechanical stress

Important: While the SIM800L is built for durability, its lifespan depends heavily on proper integration and operating conditions. Avoid exposing the module to prolonged moisture without sealing, ensure adequate power supply filtering to prevent voltage spikes, and provide sufficient airflow to manage heat. Using counterfeit or low-quality modules may compromise material standards and lead to premature failure.

Commercial Value & Applications of the SIM800L GSM Module

The SIM800L GSM module has emerged as a cornerstone in the development of cost-effective, cellular-connected devices across diverse industries. Its compact footprint, low power consumption, and robust 2G network compatibility make it an ideal solution for applications requiring reliable, long-range wireless communication. Despite the global transition to newer network technologies, the widespread availability and affordability of 2G networks—especially in developing regions—ensure the continued relevance of the SIM800L in commercial and industrial implementations.

Internet of Things (IoT)

The SIM800L is a key enabler in the IoT ecosystem, providing essential cellular connectivity for devices that operate independently of Wi-Fi or wired networks. It allows for bidirectional data transmission over GSM/GPRS networks, enabling remote data logging, cloud synchronization, and real-time alerts.

• Used in smart utility meters (electricity, water, gas) to enable automated meter reading (AMR) and reduce manual inspections
• Supports agricultural IoT systems like soil moisture sensors, weather stations, and irrigation controllers in off-grid locations
• Facilitates condition monitoring in industrial IoT, sending SMS or GPRS data when equipment thresholds are exceeded
• Enables firmware updates over-the-air (OTA) via GPRS for distributed IoT devices

Key advantage: Operates on standard SIM cards and global 2G networks, ensuring wide deployment flexibility.

Remote Monitoring & Control

The SIM800L excels in applications where physical access is limited or impractical. Its ability to send SMS alerts and transmit small data packets over GPRS makes it ideal for monitoring systems in remote or harsh environments.

• Integrated into environmental monitoring stations to report temperature, humidity, air quality, or flood levels via SMS
• Used in security systems to trigger alerts for door breaches, motion detection, or fire alarms
• Supports remote control of pumps, valves, and relays through SMS commands in industrial or agricultural settings
• Leverages the SIM card antenna for multimedia messaging (MMS), enabling image-based event reporting from surveillance cameras

Pro tip: Combine with low-power microcontrollers (e.g., ESP32, Arduino) for battery-operated, long-duration monitoring.

Automotive & Telematics

In the automotive sector, the SIM800L powers a range of vehicle tracking and diagnostic solutions. Its compact size and rugged design allow integration into tight spaces and harsh under-hood environments.

• Enables real-time GPS vehicle tracking for fleet management, theft recovery, and parental monitoring
• Supports remote diagnostics by transmitting engine fault codes (OBD-II data) via SMS or GPRS
• Used in car alarm systems to notify owners of unauthorized access or movement
• Facilitates geofencing alerts when vehicles enter or exit predefined zones

Technical note: Often paired with GPS modules (e.g., NEO-6M) to deliver location-aware services.

Healthcare & Telemedicine

The healthcare industry increasingly relies on remote patient monitoring (RPM) to improve care delivery and reduce hospital readmissions. The SIM800L supports these advancements by enabling wireless transmission of vital health data.

• Integrated into wearable medical devices to send heart rate, blood pressure, glucose levels, or ECG data to healthcare providers
• Supports emergency alert systems for elderly or at-risk patients, triggering SMS alerts during critical events
• Enables telehealth kiosks in rural areas to transmit diagnostic data where internet infrastructure is limited
• Reduces response times by allowing clinicians to intervene before conditions worsen

Critical benefit: Operates independently of local Wi-Fi, ensuring connectivity in remote or underserved regions.

Consumer Electronics

The SIM800L enhances the functionality of consumer devices by adding standalone cellular capabilities, reducing dependency on smartphones.

• Used in children’s smartwatches for voice calling, location tracking, and two-way messaging
• Integrated into fitness trackers and elderly care wearables for emergency SOS and location sharing
• Enables standalone calling and SMS in compact GPS trackers and personal safety devices
• Supports IoT-enabled home appliances (e.g., smart locks, garage openers) that can be controlled via SMS

User benefit: Provides independence from smartphones while maintaining essential communication features.

Cost-Effectiveness & Scalability

One of the primary reasons for the SIM800L’s widespread adoption is its exceptional value proposition. It offers a balance of performance, reliability, and affordability that is difficult to match in the cellular module market.

• Significantly lower cost compared to 3G, 4G, or NB-IoT modules, making it ideal for high-volume deployments
• Widely available from multiple suppliers, ensuring competitive pricing and supply chain resilience
• Low power consumption extends battery life in portable and remote applications
• Simple integration with common microcontrollers reduces development time and engineering costs

Smart investment: Enables businesses to deploy scalable, connected solutions without prohibitive upfront costs.

Professional Insight: While 2G networks are being phased out in some regions (e.g., parts of the US and Australia), the SIM800L remains viable in many countries where 2G is still active and expected to operate for several more years. For future-proofing, consider hybrid designs that allow module swapping (e.g., SIM800L to SIM7000 for NB-IoT), but for cost-sensitive, low-data applications, the SIM800L continues to deliver unmatched value.

Application Sector	Key Use Cases	Communication Method	Expected Lifespan (2G Dependent)
IoT & Industrial	Smart meters, sensor networks, automation	SMS & GPRS Data	5–7 years (region-dependent)
Remote Monitoring	Environmental sensors, security systems	SMS Alerts & MMS	4–6 years
Automotive	Vehicle tracking, telematics, alarms	SMS & GPS over GPRS	5+ years
Healthcare	Remote patient monitoring, emergency alerts	SMS & Encrypted GPRS	4–6 years
Consumer Devices	Wearables, GPS trackers, smart gadgets	Voice, SMS, Basic Data	3–5 years

Additional Considerations

• Network Longevity: Verify 2G network availability in target deployment regions before large-scale adoption
• Security: Implement encryption and authentication protocols when transmitting sensitive data over GPRS
• Antenna Design: Proper RF layout and external antenna selection are critical for reliable signal reception
• Power Management: Utilize sleep modes to maximize battery life in portable applications
• Regulatory Compliance: Ensure modules are certified for use in target markets (e.g., FCC, CE, RoHS)

How To Choose the SIM800L GSM Module: A Comprehensive Buyer’s Guide

Selecting the right SIM800L GSM module is crucial for ensuring reliable connectivity, optimal performance, and long-term durability in your electronic projects. Whether you're building IoT devices, remote sensors, or mobile communication systems, your choice should be guided by specific technical and environmental requirements. This guide breaks down the key selection criteria to help you make an informed decision based on your application needs.

Important Note: The SIM800L is a compact, low-cost GSM module widely used in embedded systems for voice, SMS, and GPRS data transmission. However, performance and reliability can vary significantly between manufacturers and module versions. Always verify specifications from trusted suppliers and test modules in real-world conditions before mass deployment.

1. Power Consumption

Power efficiency is one of the most critical factors when selecting a SIM800L module, especially for battery-powered applications such as wearables, portable trackers, and remote monitoring systems. The SIM800L typically operates at 3.4V to 4.4V and can draw up to 2A during transmission bursts, which can significantly impact battery life.

• Low-Power Variants: Some versions of the SIM800L include power-saving modes like DTM (Deep Time Mode) or sleep modes that reduce current draw to under 1mA, ideal for intermittent communication tasks.
• Battery Compatibility: Ensure your power supply or voltage regulator can handle peak current demands without voltage drops that could reset the module.
• Energy Optimization: Pair the module with efficient microcontrollers (e.g., ESP32 or Arduino in sleep mode) to minimize overall system power consumption.

Expert Tip: Use a high-capacity LDO regulator or dedicated PMIC (Power Management IC) to stabilize voltage and prevent brownout resets during signal transmission.

2. Operating Temperature Range

The environmental conditions where your device will operate play a major role in module selection. Standard SIM800L modules are rated for 0°C to +45°C, which may not suffice for industrial or outdoor use.

• Extended Temperature Versions: Industrial-grade variants operate from -30°C to +80°C, making them suitable for automotive systems, agricultural sensors, and outdoor IoT installations.
• Thermal Management: In enclosed or high-heat environments, consider heat dissipation techniques like PCB copper pours or thermal pads.
• Reliability Under Stress: Modules with wider temperature tolerances often use higher-grade components and better internal design, contributing to longer lifespan.

3. Geographic Coverage and Frequency Support

GSM network compatibility depends on regional frequency bands. The SIM800L supports quad-band GSM (850/900/1800/1900 MHz), but not all modules perform equally across all bands.

• Global Connectivity: Choose multiband modules to ensure seamless operation when deploying devices internationally.
• Regional Optimization: In North America, strong 850/1900 MHz support is essential; in Europe and Asia, 900/1800 MHz bands dominate.
• Antenna Matching: Ensure your antenna is tuned to the primary frequency band used in your target region to maximize signal strength and data throughput.

Region	Primary GSM Bands	Recommended SIM800L Support	Network Providers
North America	850 MHz, 1900 MHz	Quad-band (full support)	AT&T, T-Mobile
Europe	900 MHz, 1800 MHz	Quad-band (full support)	Vodafone, Orange
Asia-Pacific	900 MHz, 1800 MHz	Quad-band with strong 900 MHz	Airtel, Telstra
Latin America	850 MHz, 1900 MHz	Quad-band (full support)	Claro, Movistar

4. Size and Form Factor

The physical dimensions of the SIM800L module can influence your PCB layout and enclosure design, especially in compact or wearable devices.

• Compact Modules: Miniaturized versions (e.g., SIM800L vs. SIM800C) are designed for space-constrained applications like smartwatches, GPS trackers, or medical wearables.
• Standard Modules: Larger breakout boards with onboard voltage regulators, LEDs, and pin headers are better suited for prototyping, industrial controllers, or gateway devices.
• Integration Flexibility: Consider modules with castellated edges or SMD pads for direct PCB soldering to reduce footprint and improve reliability.

5. Robustness and Environmental Protection

In mission-critical or harsh environments, the durability of the SIM800L module becomes a top priority.

• Conformal Coating: Modules with protective coating resist moisture, dust, and corrosion—ideal for outdoor sensors, marine equipment, or agricultural monitoring.
• Shock and Vibration Resistance: Reinforced solder joints and sturdy packaging help maintain connectivity in mobile or industrial machinery.
• Sealed Enclosures: Even if the module isn’t coated, housing it in an IP-rated case enhances longevity in challenging conditions.

6. Additional Features and Integration Options

Some SIM800L variants come with enhanced features that can simplify design and expand functionality.

• Integrated Antenna: Built-in ceramic antennas save space but may offer lower gain than external whip antennas.
• Onboard GPS (e.g., SIM800L + GPS): Enables location tracking without additional modules—perfect for asset trackers or fleet management.
• Voltage Regulation: Modules with built-in LDOs accept a wider input range (e.g., 3.7V–12V), simplifying power design.
• UART Interface and AT Commands: Ensure compatibility with your microcontroller and verify support for essential AT commands like SMS sending, GPRS connection, and network registration.

Pro Tip: Always purchase modules from reputable suppliers or distributors to avoid counterfeit chips. Look for clear labeling, consistent PCB quality, and documentation availability. Test signal strength and stability in your intended environment before finalizing your design.

Final Selection Checklist

• ✅ Confirm voltage and current requirements match your power source
• ✅ Verify frequency band support for your geographic region
• ✅ Check operating temperature range against deployment conditions
• ✅ Evaluate size constraints and mounting options
• ✅ Assess need for environmental protection (coating, sealing)
• ✅ Determine if added features (GPS, antenna, regulator) are beneficial
• ✅ Source from trusted vendors with reliable technical support

Choosing the right SIM800L GSM module involves balancing performance, power, size, and environmental factors. By carefully evaluating your application’s unique demands, you can select a module that ensures reliable, long-term connectivity. Whether you're prototyping a smart device or deploying a large-scale IoT network, the right SIM800L variant will serve as a dependable communication backbone for your project.

Frequently Asked Questions About the SIM800L GSM Module

Q1: What is the primary function of the SIM800L GSM module?

The SIM800L is a compact and widely used GSM (Global System for Mobile Communications) module designed to enable microcontroller-based devices and IoT (Internet of Things) systems to connect to 2G cellular networks. Its core functions include:

• SMS Communication: Sending and receiving text messages for alerts, notifications, or remote commands.
• Voice Calls: Making and receiving voice calls, useful in intercom systems or emergency alert devices.
• Data Transmission: Supporting GPRS (General Packet Radio Service) for low-bandwidth internet connectivity, allowing devices to send sensor data or access basic web services.

This makes the SIM800L ideal for applications such as GPS trackers, home automation systems, remote monitoring devices, and industrial telemetry solutions where reliable, low-cost wireless communication is essential.

Q2: How does the SIM800L differ from its predecessors?

Compared to earlier GSM modules, the SIM800L offers several key improvements that enhance its usability and integration in modern electronics:

• Compact Design: The module features a smaller footprint and lightweight form factor, making it suitable for space-constrained embedded systems.
• Multi-Band Support: It operates across multiple frequency bands (typically 850/900/1800/1900 MHz), enabling global compatibility with various 2G networks.
• Improved Data Rates: Enhanced GPRS Class 10 support allows faster data transfer speeds compared to older models, improving performance for web-based tasks.
• Low Power Consumption: Optimized power usage extends battery life in portable and remote applications.
• Integrated Features: Includes built-in voltage regulation, signal amplification, and an optional onboard antenna, simplifying circuit design.

These advancements make the SIM800L more versatile, energy-efficient, and easier to deploy than previous generations of GSM modules.

Q3: What role does the SIM card play in this module?

The SIM (Subscriber Identity Module) card is essential for the operation of the SIM800L, serving several critical functions:

• Network Authentication: The SIM card authenticates the device on a mobile carrier’s network, allowing it to send and receive communications.
• Phone Number & Services: It provides the module with a unique phone number and access to services like SMS, voice, and data based on the user's subscription plan.
• Storage: Some SIM cards can store contact lists and recent messages, which can be accessed by the host microcontroller.

The SIM800L supports standard-sized SIM cards (though adapters are available for micro or nano SIMs) and requires a valid, active SIM with sufficient credit or data allowance. While the module often includes a built-in PCB antenna, external antennas can be used to improve signal strength in weak reception areas.

Q4: Is the SIM800L compatible with 4G and LTE networks?

No, the SIM800L is not compatible with 4G or LTE networks. It is specifically designed for 2G (GSM/GPRS) connectivity and operates only on legacy 2G frequency bands. As many telecom providers worldwide phase out 2G networks in favor of 4G and 5G technologies, this limitation is increasingly important to consider.

For projects requiring modern high-speed data or future-proof connectivity, alternative modules are recommended:

• SIM7600 Series: Supports 4G LTE, 3G, and 2G networks with global band coverage.
• Ai-Thinker A7670: Compact 4G LTE module with GNSS support.
• Quectel EC25: Popular 4G module used in industrial IoT applications.

Developers should assess regional network availability and long-term support when selecting a cellular module to ensure sustained operation of their devices.

Q5: What is the operating voltage range of the GSM module?

The SIM800L requires a stable power supply within the range of 3.4V to 4.4V for reliable operation. The optimal voltage is typically around 4.0V to 4.2V, especially during signal transmission when current demand spikes up to 2A.

Key power considerations include:

• Voltage Regulation: Use a high-quality voltage regulator or dedicated SIM800L breakout board with onboard LDO to prevent voltage drops.
• Power Supply Capacity: Ensure the power source can deliver sufficient current (2A peak) without sagging below 3.4V.
• Battery-Powered Devices: Lithium-ion or LiPo batteries (3.7V nominal) are commonly used but must be paired with proper boosting or regulation circuitry.
• Overvoltage Risk: Exceeding 4.4V can permanently damage the module’s internal components.

Improper power delivery is one of the most common causes of SIM800L malfunctions, including failed network registration, random reboots, or permanent hardware failure. Always use a stable, well-filtered power source for consistent performance.