Satellite Internet Modem Overview: Composition, Grades, and How It Supports Industry

Types of Satellite Internet Modems

A satellite internet modem is a critical networking device that enables internet connectivity in remote or underserved regions where traditional broadband options like cable or DSL are unavailable. Also known as a satellite transceiver or terminal, this device receives and transmits data signals via communication satellites orbiting the Earth. It converts the satellite signal into a usable digital format for computers, smartphones, and other connected devices, bridging the digital divide for rural communities, mobile professionals, and emergency services.

The choice of modem often depends on the service provider (such as HughesNet, Viasat, or Starlink), intended use, mobility requirements, and desired speed and latency performance. Below is a detailed breakdown of the main types of satellite internet modems available today.

Fixed Satellite Modem

Designed for permanent installation, this modem connects to a stationary satellite dish typically mounted on a roof or pole. It's ideal for homes and businesses in rural areas requiring stable, high-availability internet.

Advantages

• Stable and consistent connection
• Higher data throughput capabilities
• Supports multiple devices simultaneously
• Often includes advanced features like Wi-Fi 6 and QoS
• Long-term cost efficiency

Limitations

• Not portable – fixed location only
• Requires professional installation
• Vulnerable to weather interference (rain fade)
• Higher initial setup cost

Best for: Residential use, remote offices, telecommuting, rural broadband

Mobile Satellite Modem

Compact and portable, mobile modems are designed for on-the-go connectivity. These include handheld units, vehicle-mounted systems, and compact terminals used in RVs, boats, or emergency response vehicles.

Advantages

• High portability and ease of transport
• Enables connectivity in remote or disaster-stricken areas
• Quick deployment in emergency situations
• Supports voice, data, and GPS services
• Ideal for fieldwork and mobile operations

Limitations

• Lower bandwidth compared to fixed systems
• Battery life limitations
• Smaller antenna reduces signal strength
• Higher per-data costs

Best for: Emergency responders, journalists, explorers, maritime and aviation use, overland travelers

Broadcast Satellite Modem

Used primarily for one-way data transmission, this modem receives high-speed data from broadcast satellites (e.g., for news feeds, software updates, or distance learning). Often integrated with VSAT (Very Small Aperture Terminal) networks and hybrid systems that combine satellite reception with terrestrial return paths (like cellular or Wi-Fi).

Advantages

• High-speed downstream data delivery
• Efficient for content distribution (TV, radio, data)
• Low latency for broadcast applications
• Cost-effective for large-scale content dissemination
• Can integrate with GSM or LTE for two-way communication

Limitations

• Limited or no upstream (return) capability without hybrid setup
• Requires additional infrastructure for full interactivity
• Niche applications reduce general availability
• Complex integration with terrestrial networks

Best for: News broadcasting, distance education, corporate content delivery, government communications

Two-Way VSAT Modem

An advanced category often grouped under fixed or mobile systems, Two-Way VSAT modems support full-duplex communication, enabling both upload and download via satellite. These are commonly used in enterprise, military, and offshore operations.

Advantages

• Full internet functionality (upload and download)
• Secure and reliable for mission-critical operations
• Scalable for enterprise networks
• Supports VoIP, video conferencing, and cloud services
• Operates independently of ground infrastructure

Limitations

• Expensive equipment and service plans
• Requires precise antenna alignment
• Higher power consumption
• Regulatory licensing may be required

Best for: Offshore platforms, military bases, remote mining operations, disaster recovery centers

Type	Mobility	Speed	Use Case	Installation Complexity
Fixed Satellite Modem	None	High (10–100 Mbps)	Home internet, remote offices	High (professional)
Mobile Satellite Modem	High	Moderate (2–10 Mbps)	Emergency response, fieldwork	Low to Medium
Broadcast Satellite Modem	Low	High (download only)	Content distribution, education	Medium
Two-Way VSAT Modem	Low to Medium	High (with low latency options)	Enterprise, military, offshore	High

Expert Tip: When selecting a satellite modem, always verify compatibility with your service provider. Newer systems like Starlink use proprietary modems that are not interchangeable with traditional providers like HughesNet or Viasat. Additionally, consider future-proofing by choosing models that support firmware updates and emerging protocols such as DVB-S2X for improved efficiency.

Functions and Features of Satellite Internet Modems

Satellite internet modems serve as the critical bridge between space-based communication networks and terrestrial digital devices. These advanced devices enable internet access in remote, rural, and mobile environments where traditional broadband infrastructure is unavailable. Understanding their core functions and technical features is essential for selecting, installing, and optimizing satellite internet performance.

Core Functions of Satellite Modems

Signal Conversion

The primary role of a satellite internet modem is signal conversion—transforming high-frequency radio waves received from the satellite dish into digital data that can be used by computers, smartphones, and other networked devices. This process, known as demodulation, extracts internet protocol (IP) packets from the incoming RF signal.

Conversely, when sending data upstream, the modem modulates digital information into radio signals compatible with satellite transmission. This bidirectional translation ensures seamless communication between ground-based users and geostationary or low Earth orbit (LEO) satellites.

Data Transmission Protocols

Modems manage data transmission using specialized satellite communication protocols such as TDMA (Time Division Multiple Access) or SCPC (Single Channel Per Carrier). These technologies regulate how data packets are segmented, prioritized, and transmitted to maximize bandwidth efficiency and minimize interference.

TDMA allows multiple users to share the same frequency channel by assigning time slots, while SCPC dedicates a full channel to a single user for consistent throughput—ideal for enterprise or high-demand applications.

Key Technical Features

Frequency Band Compatibility

Satellite systems operate across different frequency bands, including C-band (4–8 GHz), Ku-band (12–18 GHz), and Ka-band (26–40 GHz). Each band offers distinct advantages: C-band provides reliable performance in adverse weather, Ku-band balances speed and coverage, and Ka-band supports higher data rates with smaller antennas.

Modern satellite modems must be compatible with the specific frequency used by the service provider. Mismatched frequencies result in failed connections or degraded performance.

Spread Spectrum Technology

To combat signal interference, noise, and multipath fading (signal reflections), many satellite modems employ spread spectrum techniques. These methods spread the signal across a wider bandwidth, enhancing resistance to jamming and improving overall link reliability.

This technology is particularly beneficial in urban areas or regions with electromagnetic interference, ensuring stable connectivity even under challenging conditions.

Latency Management

Satellite internet inherently experiences higher latency—typically 500–700 ms for geostationary satellites—due to the long distance signals travel (approximately 22,000 miles to orbit and back). While this delay cannot be eliminated, modem hardware and firmware play a significant role in minimizing processing overhead.

High-performance modems use optimized data compression, TCP acceleration, and Quality of Service (QoS) algorithms to reduce perceived latency, making applications like video conferencing and online gaming more usable despite the physical limitations.

Integrated Router Capabilities

Many modern satellite modems come with built-in routers and Wi-Fi access points, eliminating the need for additional networking hardware. These all-in-one units support multiple wired and wireless devices, simplifying setup for home, office, or mobile deployments.

Integrated models often include firewall protection, parental controls, and guest network features, providing a complete networking solution ideal for remote locations or temporary installations.

Ports and Connectivity Options

Satellite modems typically offer a range of physical interfaces to support diverse connectivity needs. Standard features include one or more Ethernet ports (10/100/1000 Mbps) for wired connections to computers, routers, or IP cameras.

Some models also include USB ports for direct device connection or firmware updates, coaxial RF ports for linking to the satellite dish, and PoE (Power over Ethernet) support for simplified power delivery in outdoor or hard-to-reach installations.

Size and Mounting Flexibility

Modem designs vary from compact desktop units suitable for indoor placement to ruggedized enclosures built for outdoor mounting near the satellite dish. Outdoor-rated models are weatherproof, UV-resistant, and designed to withstand extreme temperatures and humidity.

Mounting options include wall brackets, pole mounts, or integration into existing dish assemblies, allowing flexible deployment in residential, commercial, maritime, or vehicular environments.

Power Requirements and Efficiency

Power consumption varies significantly between models, with basic units drawing 10–20 watts and high-performance modems requiring up to 50 watts or more. This is an important consideration for off-grid or solar-powered installations where energy efficiency is critical.

Most modems use AC power adapters, but some support Power over Ethernet (PoE), enabling power delivery through the same cable used for data. This reduces cabling complexity and enhances reliability in distributed network setups.

Feature	Impact on Performance	Selection Considerations
Frequency Band Support	High	Ensure compatibility with your satellite service (e.g., Ku-band for Viasat, Ka-band for Starlink)
Integrated Wi-Fi Router	High	Choose integrated models for plug-and-play setups; separate router for advanced networking control
Latency Optimization	High	Look for modems with TCP acceleration and QoS for real-time applications
Port Availability	Medium	Ensure sufficient Ethernet ports and optional USB/PoE based on your device count
Outdoor Durability	Medium	Required for direct dish-side mounting; otherwise, indoor placement is sufficient
Power Consumption	Medium	Lower wattage preferred for off-grid or backup power scenarios

Best Practices for Optimal Use

Verify Compatibility: Always confirm that the modem is approved by your satellite internet provider and matches the required frequency and protocol standards.

Optimize Placement: Install the modem close to the satellite dish to minimize signal loss in coaxial cables, and ensure proper ventilation to prevent overheating.

Use Surge Protection: Satellite systems are vulnerable to lightning strikes; use surge protectors on both power and coaxial lines to safeguard the modem.

Keep Firmware Updated: Regularly check for firmware updates from the manufacturer to benefit from performance improvements, security patches, and new features.

Monitor Performance: Use built-in diagnostics or third-party tools to track latency, packet loss, and signal strength for proactive troubleshooting.

Important: Using an incompatible or uncertified modem may result in service disruption, reduced speeds, or violation of service agreements. Always consult your satellite internet provider before purchasing or replacing equipment. Additionally, improper installation—especially of outdoor units—can lead to signal degradation or hardware damage. When in doubt, seek professional installation support.

Applications for Satellite Internet Modem

Satellite internet modems are versatile communication devices that bridge the digital divide by delivering reliable internet access in areas where traditional broadband infrastructure is unavailable or unreliable. These modems convert satellite signals into usable internet connectivity, enabling a wide range of applications across diverse environments—from remote wilderness to emergency response zones. Understanding their key use cases helps businesses, governments, and individuals make informed decisions about connectivity solutions.

Rural Connectivity

Satellite internet modems provide essential connectivity for homes and facilities in rural and underserved regions. Unlike urban areas with fiber or cable networks, many rural communities lack terrestrial infrastructure, making satellite the only viable option.

• Enables remote education, telehealth services, and online banking in isolated communities
• Supports critical operations at military bases, scientific research stations, and oil/gas extraction sites
• Offers scalable solutions for expanding broadband access without costly ground-based installations

Key benefit: Ensures digital inclusion for populations beyond the reach of conventional ISPs

Remote Geographic Regions

In geographically challenging areas such as mountainous zones, dense jungles, deserts, or Arctic regions, laying cables or establishing cellular towers is often impractical or prohibitively expensive.

• Connects indigenous communities, forest rangers, and conservation teams in protected natural areas
• Facilitates real-time monitoring of environmental conditions and wildlife tracking systems
• Enables government agencies to maintain communication with remote outposts and border patrol units

Critical advantage: Provides consistent coverage regardless of terrain complexity or distance from urban centers

Mobile and On-the-Go Use

Portable satellite modems empower mobile professionals and adventurers to stay connected while traveling across remote or off-grid locations.

• Truck drivers and logistics fleets use them for GPS tracking, dispatch communication, and route optimization
• RV owners and campers maintain internet access for navigation, weather updates, and entertainment
• Mariners and boaters rely on satellite modems for safety alerts, AIS data, and emergency distress signaling
• Hikers and expedition teams use compact units to share location data and coordinate with base camps

Pro tip: Modern portable modems are lightweight, battery-powered, and compatible with smartphones and tablets

Emergency and Disaster Response

When hurricanes, earthquakes, floods, or wildfires disrupt terrestrial networks, satellite internet remains operational, serving as a lifeline during crises.

• First responders deploy satellite modems to set up temporary command centers and coordinate rescue efforts
• Hospitals and field clinics maintain access to patient records and telemedicine platforms
• Relief organizations communicate with headquarters and manage supply chains in affected zones
• Local governments issue public alerts and coordinate evacuations even when power grids fail

Lifesaving role: Satellite systems operate independently of local infrastructure, ensuring continuity during blackouts

Broadcasting and Field Journalism

News crews and media teams use satellite internet modems to transmit high-quality content from remote or conflict zones where other connectivity options are unavailable.

• Live video streaming enables real-time reporting from disaster sites, war zones, or political uprisings
• Photojournalists upload images and video footage directly to editorial desks without delays
• Backpack-sized satellite terminals allow rapid deployment in unpredictable environments
• Supports IP-based broadcast workflows, including cloud editing and content distribution

Industry standard: Satellite news gathering (SNG) systems are essential tools for global news networks

Scientific Research & Development

Researchers in extreme environments—from Antarctic bases to deep-sea exploration vessels—depend on satellite internet for data transfer and collaboration.

• Real-time transmission of climate, seismic, and ecological data to global research databases
• Access to cloud computing resources, software updates, and academic journals from remote labs
• Supports autonomous drones, rovers, and underwater sensors that require constant data synchronization
• Facilitates virtual collaboration with international teams during long-duration missions

Innovation enabler: Enables breakthroughs in space exploration, marine biology, and atmospheric science

Data Backup & Secure Synchronization

Satellite modems support secure, long-distance data replication and cloud backup, which is vital for distributed operations and mission-critical systems.

• Robotic systems in remote locations sync sensor data and control algorithms with central AI servers
• Oil rigs and mining operations back up operational logs and safety reports to offsite servers
• Government and defense agencies maintain redundant communication channels across geographically dispersed units
• Cloud-based disaster recovery systems use satellite links as failover connections

Security note: Encrypted satellite links provide secure transmission for sensitive or classified data

Emerging and Future Applications

As satellite technology advances, new applications continue to emerge, driven by lower latency, higher bandwidth, and improved affordability.

• Integration with IoT networks for smart agriculture, remote asset monitoring, and wildlife conservation
• Support for telemedicine robots and remote surgery in isolated clinics
• Expansion of low Earth orbit (LEO) constellations like Starlink, offering near-broadband speeds globally
• Use in autonomous vehicles operating in off-road or extraterrestrial environments

Future outlook: Next-gen satellite internet will enable real-time AI processing and edge computing in remote areas

Professional Insight: When recommending satellite internet solutions, consider bandwidth requirements, latency sensitivity, mobility needs, and environmental durability. For mission-critical applications, prioritize systems with built-in redundancy, encryption, and Quality of Service (QoS) features. Always verify service availability and data caps with the provider to ensure long-term reliability.

Application	Typical Users	Bandwidth Needs	Key Requirements
Rural Internet Access	Homeowners, schools, clinics	10–50 Mbps	Reliability, affordability, ease of installation
Emergency Response	First responders, NGOs	5–20 Mbps (prioritized)	Rapid deployment, portability, battery backup
Mobile Connectivity	Truckers, boaters, RVers	5–30 Mbps	Portability, weather resistance, low power consumption
Field Broadcasting	Journalists, media crews	20–100 Mbps (uplink)	Low latency, HD video support, secure transmission
Scientific Research	Scientists, explorers	10–50 Mbps	Data integrity, 24/7 uptime, encryption
Industrial Data Sync	Engineers, robotics teams	5–30 Mbps	Secure protocols, automated backups, API integration

Additional Considerations

• Latency Awareness: Geostationary satellites have higher latency (~600ms); LEO systems reduce this to ~20–50ms, improving real-time applications
• Data Caps: Many satellite plans include monthly limits—crucial for data-intensive uses like video streaming or cloud backups
• Weather Resilience: While generally reliable, heavy rain or snow can temporarily affect signal strength (rain fade)
• Installation: Requires clear line-of-sight to the satellite; professional setup ensures optimal performance
• Cost vs. Value: Higher upfront costs are often justified by the critical nature of connectivity in remote or emergency scenarios

How to Choose the Right Satellite Internet Modem

Selecting the appropriate satellite internet modem is a crucial decision that directly impacts connectivity performance, reliability, and user experience—especially in remote or rural areas where traditional broadband options are unavailable. Unlike standard cable or DSL modems, satellite modems are highly specialized devices designed to communicate with specific satellite networks. Choosing the wrong model can result in incompatibility, poor speeds, or service outages.

Important Note: Satellite modems are typically not interchangeable between service providers. Each satellite network uses proprietary technology, encryption, and frequency bands, meaning a modem must be specifically certified for use with your chosen provider.

Key Factors When Choosing a Satellite Internet Modem

Before purchasing a satellite modem, it's essential to understand the technical, environmental, and financial aspects that influence performance and long-term usability. Below are the most critical considerations:

1. Ensure Compatibility with Your Service Provider

   Satellite internet modems are not universal. Each provider—such as HughesNet, Viasat, Starlink, or regional satellite operators—requires a specific modem model that is engineered to interface with their satellite constellation and ground network.

   • Always confirm with your ISP which modem models are approved for use.
   • Some providers lease or include the modem with service plans, while others allow third-party purchases if certified.
   • Using an unapproved or incompatible modem may void service agreements or prevent activation.
2. Understand Technical Features and Capabilities

   Modern satellite modems vary significantly in performance, supported bandwidth, and advanced features. Understanding these differences helps match the device to your usage needs.

   • User Capacity: Consider how many devices will connect simultaneously. Higher-end models support more concurrent users without performance degradation.
   • Security Features: Look for built-in firewalls, WPA3 encryption, and firmware updates to protect against cyber threats.
   • Throughput & Latency Optimization: Some modems include Quality of Service (QoS) settings to prioritize traffic (e.g., video calls or streaming).
   • Firmware Support: Ensure the modem receives regular software updates to maintain security and performance.
3. Consider Built-in Router and Wi-Fi Functionality

   In remote locations, a standalone modem may not be sufficient. Most users benefit from a combined satellite modem/router with Wi-Fi capabilities.

   • A built-in router eliminates the need for additional hardware and simplifies setup.
   • Look for Wi-Fi 5 (802.11ac) or Wi-Fi 6 (802.11ax) support for better coverage and speed.
   • Check the number of Ethernet ports (typically 2–4) for wired device connections like desktops or security systems.
   • For larger homes or offices, consider models with mesh networking support or external antenna options.
4. Evaluate Environmental and Installation Requirements

   Satellite internet depends on a clear line of sight to the sky. The modem works in tandem with the outdoor satellite dish (antenna), so environmental factors matter.

   • Ensure the modem is compatible with the outdoor unit (ODU) and coaxial cabling.
   • In areas with extreme weather, choose hardware rated for temperature resilience and moisture resistance.
   • Some modems offer signal strength indicators or diagnostic tools to assist with alignment and troubleshooting.
5. Understand Total Cost of Ownership

   Beyond the initial purchase price, several ongoing costs should be factored into your decision.

   • Equipment Cost: Modems can range from $100 for basic models to over $500 for advanced, provider-certified units.
   • Installation Fees: Professional installation may be required, especially for dish alignment and network configuration.
   • Service Plans: Monthly subscription fees vary by provider and data allowance; some plans include modem rental.
   • Maintenance & Upgrades: Budget for potential replacements or technology shifts (e.g., migration to low-Earth orbit networks).
6. Remote Management and Control Options

   For businesses, managed networks, or multi-site deployments, remote access to the modem is invaluable.

   • Look for modems with web-based or mobile app interfaces for monitoring usage, rebooting, or adjusting settings.
   • Advanced models support SNMP, API access, or integration with network management systems.
   • Remote diagnostics can reduce downtime and support faster troubleshooting.

Selection Criteria	What to Look For	Common Mistakes to Avoid	Provider Examples
Compatibility	ISP-certified model, matching firmware version	Assuming modems are interchangeable across brands	HughesNet Gen6, Viasat KU2, Starlink Standard Router
Wi-Fi & Connectivity	Wi-Fi 6, 4+ Ethernet ports, MU-MIMO support	Overlooking Wi-Fi range in large buildings	Starlink WiFi Router, Viasat Wi-Fi Gateway
Security	Firewall, WPA3, automatic updates	Using default passwords or outdated firmware	All major providers offer secure gateways
Installation	Easy alignment tools, signal meter, outdoor unit compatibility	DIY installation without proper expertise	Starlink Self-Installation Kit, HughesNet Pro Install
Management	Mobile app, remote reboot, usage analytics	Ignoring remote access for off-site monitoring	HughesNet My Account, Viasat Connect App

Expert Tip: If you're deploying satellite internet for a business, school, or community center, consider working directly with the provider to request enterprise-grade equipment with enhanced support, redundancy options, and service-level agreements (SLAs).

Final Recommendations

• Always verify modem compatibility with your satellite internet provider before purchasing.
• Opt for a modem-router combo with strong Wi-Fi if serving multiple users or devices.
• Choose models with remote management features for easier maintenance and troubleshooting.
• Factor in total costs—including equipment, installation, and monthly service—when budgeting.
• Keep firmware updated to ensure optimal performance, security, and compatibility with network upgrades.
• Consult with your ISP’s technical support team if unsure about model selection or installation requirements.

Choosing the right satellite internet modem is more than just a hardware decision—it's about ensuring reliable, secure, and scalable connectivity for your specific environment and usage needs. By carefully evaluating compatibility, features, and long-term costs, you can select a modem that delivers consistent performance, even in the most remote locations.

Frequently Asked Questions About Satellite Internet Modems

Q1: How is a satellite internet modem installed?

Satellite internet modem installation is typically handled by a professional technician from the service provider. The process involves several key steps:

• Dish Placement: The satellite dish is mounted in a location with a clear line of sight to the southern sky (in the northern hemisphere), usually on a roof, pole, or exterior wall.
• Alignment: The dish must be precisely aligned to communicate with the orbiting satellite, which requires specialized tools to optimize signal strength and quality.
• Cabling: A coaxial cable connects the dish to the indoor satellite modem, ensuring minimal signal loss over the distance.
• Modem Setup: The modem is powered and configured to authenticate with the satellite network. Once online, it can distribute internet via Wi-Fi or Ethernet.

After installation, users can connect their router, computer, or other devices using an Ethernet cable or by joining the modem’s built-in Wi-Fi network. Some providers offer self-installation kits for basic setups, but professional installation is recommended for optimal performance.

Q2: What is the difference between a satellite modem and a cable modem?

The fundamental difference lies in how each connects to the internet infrastructure:

Feature	Satellite Modem	Cable Modem
Connection Type	Uses radio signals transmitted to and from a geostationary satellite in space.	Relies on a physical coaxial cable connection to a local cable network.
Availability	Available in most rural and remote areas where terrestrial infrastructure is lacking.	Limited to urban and suburban regions with existing cable lines.
Latency	Higher latency (500–700ms) due to long signal travel distance (~22,000 miles to satellite).	Lower latency (10–30ms), ideal for real-time applications like gaming or video calls.
Speed	Typically offers 25–100 Mbps download, depending on the service plan.	Often provides faster speeds, ranging from 100 Mbps to over 1 Gbps.
Weather Sensitivity	Performance may degrade during heavy rain or storms (known as "rain fade").	Generally unaffected by weather conditions.

In summary, while satellite internet offers broad geographic coverage, cable internet delivers faster speeds and lower latency where available.

Q3: Can one use a phone with a satellite internet modem?

Yes, you can use your phone with a satellite internet connection in several ways:

• Wi-Fi Hotspot: Most satellite modems come with built-in Wi-Fi or are connected to a router, allowing smartphones to connect wirelessly just like any home network.
• Mobile Tethering: If your phone has cellular service, you can reverse tether it to share its data—though this is less common with satellite setups.
• Voice over IP (VoIP): Many satellite internet plans support VoIP services such as Skype, Zoom, or provider-specific phone services. If the modem includes a telephone port (FXS), you can plug in a standard landline phone for direct calling.
• Emergency Calling: Note that traditional 911 services may not function automatically over VoIP; users should verify emergency calling capabilities with their provider.

While voice calls are possible, high latency may affect call quality, especially for real-time conversations. Using HD voice or noise-canceling headsets can help improve clarity.

Q4: What is the difference between a satellite modem and a satellite dish?

Although they work together, the satellite modem and the dish serve distinct roles in the internet delivery system:

• Satellite Dish (Antenna): This outdoor component captures and transmits two-way radio signals to and from a communications satellite in geostationary orbit. It acts as the physical interface between your location and the space-based network.
• Satellite Modem: Located indoors, the modem processes the analog signals received from the dish into digital data that your devices can use. It also converts outgoing digital data into signals the dish can transmit back to the satellite.

Think of the relationship like this: the dish is the “antenna” that sends and receives signals, while the modem is the “translator” that converts those signals into usable internet for your home network. Both are essential for satellite internet to function properly.

Modern systems often integrate tight coordination between the modem and dish, with some providers using advanced phased-array antennas (like Starlink) that combine elements of both into a single unit for easier setup and better performance.