Buy RMS Credits For Teltonika Devices

Buy RMS Credits for Teltonika

In-depth guide for RUT240 and the wider Teltonika range (Dec 2025)

Teltonika RMS is the control panel for your entire Teltonika deployment. If you use a RUT240, or any Teltonika router from the RUT2xx, RUT9xx, RUTX or 5G series, you’ll eventually need RMS Credits. They’re how you pay for remote access, monitoring, configuration, firmware updates, and remote device access.

This post breaks down how RMS works, what credits actually do, how many you need, and why RUT240 owners in particular should treat RMS as essential rather than optional.


What is Teltonika RMS?

RMS (Remote Management System) is Teltonika’s cloud platform used to manage routers and gateways from a single login. Instead of logging into each RUT240 individually, the platform gives you a central dashboard that lets you:

  • See device status in real time
  • Push or roll back configurations
  • Run firmware updates in bulk
  • Monitor mobile signal and data usage
  • Set alerts, reports, and automation
  • Remotely access devices behind the router

Everything is browser-based. No VPN setup, no port forwarding, no fiddling with public IPs. The system is hosted on a secure cloud backend and communicates with each router using encrypted channels. It’s designed specifically for IoT deployments where routers are spread across dozens or hundreds of live sites.


Why RUT240 Users Rely on RMS Credits

The RUT240 is one of Teltonika’s most widely deployed industrial 4G routers. It’s used in vending, telemetry, CCTV, renewable energy, EV charging, kiosks, and agricultural sites. These are not the sort of installations where engineers want to be driving out just to click a “reboot” button.

With RMS active, you can:

  • Diagnose SIM or network issues
  • Inspect signal strength and serving cell info
  • View detailed logs
  • Run speed tests
  • Change APN settings remotely
  • Recover misconfigured routers
  • Upgrade firmware without sending someone to site

Most support teams will tell you the same thing: RMS pays for itself the moment one trip is avoided.


What Are RMS Credits?

RMS Credits are the pay-as-you-go currency of Teltonika’s RMS platform. They are simple:

  • 1 RMS Credit = 30 days of RMS Management for one device.

That’s it. No complicated tiers, no hidden rules. Credits sit in your RMS account until you assign them to a device. When that device’s 30-day period is up, another credit is drawn.

Think of credits as “device-months”

It helps to treat credits as blocks of time:

CreditsWhat You Can Cover
1 credit1 device for 1 month
12 credits1 device for 12 months or 3 devices for 4 months each
24 credits2 devices for 12 months, or 24 devices for 1 month
60 credits5 devices for 12 months, or 60 devices for 1 month

With a single RUT241, it’s straightforward: keep at least 12 credits in your account and you’re covered for a year.

With multiple devices, you can allocate exactly as needed. Nothing is locked to a specific router forever.


RMS vs RMS Management Packs vs Data Packs

Teltonika gives three ways to pay for RMS:

RMS Credits

Flexible, month-by-month. Best for small deployments, testing phases, short-term projects or intermittent use.

RMS Management Packs

These are fixed-term licences (3-year, 5-year, 10-year) for a specific device. They work well when the device will remain installed long-term and there’s a formal maintenance contract.

RMS Data Packs

These apply to RMS VPN and RMS Connect. They cover the data used when remotely accessing devices behind the router or building VPN tunnels. If you only use RMS for monitoring and management (most RUT240 users), you rarely need these.

For a typical RUT241 deployment – vending machines, EV chargers, signage, CCTV, BMS – credits are the simplest and most cost-effective route.


What You Can Do With RMS Credits

(A practical view for RUT240 owners)

1. Remote access to the router

Log in to the RUT240 from your browser regardless of IP addressing or SIM type.

  • No VPN to configure
  • No port forwarding
  • No public IP required
  • Works with private, CGNAT, and roaming SIMs

2. Remote access to LAN devices

The big win for engineers is RMS Connect.

You can open HTTP, HTTPS, RDP, SSH or VNC sessions to devices behind the router. For RUT240 deployments this means:

  • Accessing CCTV NVRs
  • Managing PLCs and RTUs
  • Updating signage controllers
  • Configuring industrial PCs
  • Connecting to EV charging back-ends
  • Talking to sensors or telemetry equipment

You bypass all networking complexity.

3. Bulk firmware updates

RMS lets you select hundreds of RUT241s and update them all to the same firmware in one batch. If you’ve ever tried to roll out security patches on-site, this is a lifesaver.

4. Automated alerts and reporting

The platform can tell you when a device:

  • Goes offline
  • Changes SIM
  • Drops signal
  • Hits a data cap
  • Reboots unexpectedly
  • Attempts an unauthorised login

You can build weekly or monthly reports for customers.

5. Configuration templates

This is especially helpful for RUT240 users deploying identical units.

Set up one router exactly the way you want. Save its configuration as a template. Push it to every new device in the field with a couple of clicks.


How Many RMS Credits Should You Buy?

RUT240 projects generally fall into three categories.

Small deployments (1 to 5 routers)

Buy 12 to 24 credits.
You’ll use one per month. Keeping a buffer ensures you never accidentally lapse.

Medium deployments (5 to 50 routers)

Buy 50 to 200 credits depending on how often you use RMS for troubleshooting and updates.

Large deployments (50 to 500+ routers)

Buy in bulk – 500+ credits.
It simplifies admin and gives you cost predictability for the year.

If you’re using RMS VPN heavily, consider adding RMS Data Packs, but most RUT240 use cases don’t require this.


Why Not Run Without RMS?

A RUT240 is perfectly usable without RMS, but you lose:

  • Remote firmware control
  • Remote troubleshooting
  • Config rollback
  • Secure access to devices behind the router
  • Central reporting
  • Alarms and notifications
  • Bulk configuration management

You end up treating every router as a standalone box instead of part of a managed fleet.

For most customers, the first time they avoid a single site visit, the credits have paid for themselves.


How to Add RMS Credits to Your Account

  1. Sign in to RMS.
  2. Go to Credits in the left-hand menu.
  3. Click Add Credits.
  4. Enter the code supplied after purchase.
  5. Credits appear instantly in your account.
  6. Go to Devices, select the router, assign credits, and you’re covered for 30 days.

Teltonika gives one free credit with each new router, but after that it’s down to the credits you buy.


Using RMS With a RUT240 – Real-World Example

Here’s how a typical RUT240 deployment uses RMS:

Scenario:
A RUT240 is installed in a control cabinet at a remote site running a telemetry app.

Without RMS:
Someone rings saying the site is offline.
You get in the van.
Drive two hours.
Open the cabinet.
Click “Reboot”.
Check APN.
Return home.

With RMS:
You log into RMS.
You see the router is online but has no mobile data.
You check signal and serving cell info – poor signal spike.
Reboot modem remotely.
Router connects.
Job done in five minutes.

This is why RMS Credits are treated as operational budget rather than an extra.


Summary

If you use a Teltonika Router (RUT200, RUT206, RUT241, RUT906, RUTX50 etc, RMS Credits give you:

  • Complete remote access
  • Time-saving troubleshooting
  • Secure access to devices behind the router
  • Bulk configuration
  • Firmware control
  • Proper fleet management

One credit runs one device for 30 days.
Buy them, load them into your account, and assign them as needed.

For industrial deployments, it’s one of the cheapest and most effective ways to keep things running smoothly.

RUT241 eSIM Router

The Teltonika RUT241 eSIM 4G Router: Revolutionizing M2M and IoT ConnectivityThe Teltonika RUT241 eSIM 4G router represents a significant advancement in industrial-grade connectivity solutions for Machine-to-Machine (M2M) and Internet of Things (IoT) applications. This compact yet powerful device combines the latest in eSIM technology with robust 4G LTE capabilities, offering unparalleled flexibility and reliability for a wide range of industrial and IoT deployments.

RUT241 eSIM Router

Key Features of the Teltonika RUT241 eSIM 4G Router

The RUT241 builds upon the success of its predecessor, the RUT240, while introducing several key enhancements:

  • eSIM Technology: The router comes equipped with embedded SIM (eSIM) functionality, eliminating the need for physical SIM cards.
  • 4G LTE Connectivity: Supports Cat 4 LTE with speeds up to 150 Mbps, ensuring fast and reliable data transfer.
  • Dual Ethernet Ports: Features 1 WAN and 1 LAN port for flexible network configurations.
  • Wi-Fi Capabilities: Includes Wi-Fi functionality with hotspot support, allowing for up to 50 simultaneous connections.
  • Industrial-Grade Design: Compact and robust construction suitable for harsh environments.
  • Advanced Security Features: Supports various VPN protocols, firewall, and other security measures.
  • RutOS Software: Powered by Teltonika’s proprietary operating system, offering advanced features and remote management capabilities.

Understanding eSIM Technology

Embedded SIM (eSIM) technology represents a significant shift in how devices connect to cellular networks. Unlike traditional physical SIM cards, eSIMs are integrated directly into the device’s hardware during manufacturing. This integration offers several advantages:

  1. Remote Provisioning: eSIMs can be programmed and reprogrammed remotely, allowing for easy switching between carriers without physically changing SIM cards.
  2. Space Efficiency: The elimination of the physical SIM slot allows for more compact device designs and potentially larger batteries.
  3. Enhanced Durability: With no removable parts, eSIM-equipped devices are more resistant to dust and moisture ingress.
  4. Simplified Logistics: eSIMs eliminate the need to manage and distribute physical SIM cards, streamlining device deployment and management.

M2M and IoT Applications

The Teltonika RUT241 eSIM 4G router is particularly well-suited for a wide range of M2M and IoT applications, including:

  1. Industrial Automation: Providing reliable connectivity for remote monitoring and control of industrial equipment.
  2. Smart Cities: Enabling communication for various urban infrastructure components like traffic management systems and public utilities.
  3. Fleet Management: Offering robust connectivity for vehicle tracking and telematics applications.
  4. Remote Monitoring: Supporting deployments in hard-to-reach locations for environmental monitoring, agriculture, and more.
  5. Retail and Point-of-Sale: Ensuring reliable connectivity for payment systems and inventory management.

Benefits for M2M/IoT Installers and Users

The adoption of the Teltonika RUT241 eSIM 4G router offers numerous benefits for both installers and end-users in the M2M/IoT space:

  1. Simplified Deployment: eSIM technology allows for easier installation and configuration, reducing on-site time and complexity.
  2. Flexibility: The ability to switch carriers remotely provides greater flexibility in choosing and changing service providers.
  3. Cost Efficiency: Elimination of physical SIM cards reduces logistical costs and simplifies inventory management.
  4. Enhanced Security: Built-in security features protect sensitive data and ensure compliance with industry standards.
  5. Future-Proofing: eSIM technology allows for easy updates and adaptations to changing network requirements.
  6. Global Deployment: Simplified management of devices across multiple regions and carriers.
  7. Reliability: Industrial-grade design and advanced failover capabilities ensure consistent connectivity in challenging environments.

Conclusion

The Teltonika RUT241 eSIM 4G router represents a significant step forward in M2M and IoT connectivity solutions. By combining the flexibility of eSIM technology with robust 4G LTE capabilities and industrial-grade design, it offers a versatile and reliable platform for a wide range of applications. For installers and users in the M2M/IoT space, this device promises to simplify deployments, reduce costs, and enhance overall performance and reliability.

As the IoT landscape continues to evolve, solutions like the RUT241 will play a crucial role in enabling the next generation of connected devices and smart systems. With its advanced features and future-proof design, the Teltonika RUT241 eSIM 4G router is poised to become a cornerstone of industrial IoT connectivity.

Teltonika RUT241

The Teltonika RUT241 is the modified version of their all-time bestseller RUT240 that inherited its’ best features, including industrial design, compact size, multiple connection interfaces, and compatibility with RMS.

Equipped with embedded 4G LTEmodem with single SIM slot., Wi-Fi, and two Ethernet ports, this router offers unstoppable connection continuity with a backup through automatic failover. Digital Inputs and Outputs coupled with advanced RutOS software enable solution automation scenarios. The Teltonika RUT241 is an excellent fit in various IoT and M2M solutions that require easy setup, reliable network, and remote accessibility.

Teltonika RUT241 Key Features

  • 4G LTE Cat 4 with speeds up to 150 Mbps.
  • WAN Failover: Automatically switches to available backup connection.
  • Wireless Access Point with Hotspot functionality.
  • Compact size, easy integration.
  • Digital Input/Output for remote monitoring and control.
  • Teltonika Remote Management System compatible (RMS credits sold separately).

MOBILE

  • Mobile module4G (LTE) – Cat 4 up to 150 Mbps, 3G – Up to 42 Mbps, 2G – Up to 236.8 kbps
  • StatusSignal strength (RSSI), SINR, RSRP, RSRQ, EC/IO, RSCP, Bytes sent/received, connected band, IMSI, ICCID
  • SMSSMS status, SMS configuration, send/read SMS via HTTP POST/GET, EMAIL to SMS, SMS to EMAIL, SMS to HTTP, SMS to SMS, scheduled SMS, SMS autoreply, SMPP
  • USSDSupports sending and reading Unstructured Supplementary Service Data messages
  • Black/White listOperator black/white list
  • Multiple PDNPossibility to use different PDNs for multiple network access and services
  • Band managementBand lock, Used band status display
  • APNAuto APN
  • BridgeDirect connection (bridge) between mobile ISP and device on LAN
  • PassthroughRouter assigns its mobile WAN IP address to another device on LAN

WIRELESS

  • Wireless modeIEEE 802.11b/g/n, Access Point (AP), Station (STA)
  • WiFi securityWPA2-Enterprise – PEAP, WPA2-PSK, WEP, WPA-EAP, WPA-PSK; AES-CCMP, TKIP, Auto Cipher modes, client separation
  • SSID/ESSIDSSID stealth mode and access control based on MAC address
  • WiFi usersUp to 50 simultaneous connections
  • Wireless HotspotCaptive portal (Hotspot), internal/external Radius server, built in customizable landing page

ETHERNET

  • WAN1 x WAN port  10/100 Mbps, compliance IEEE 802.3, IEEE 802.3u standards, supports auto MDI/MDIX
  • LAN1 x LAN port, 10/100 Mbps, compliance with IEEE 802.3, IEEE 802.3u standards, supports auto MDI/MDIX

NETWORK

  • RoutingStatic routing, Dynamic routing (BGP, OSPF v2, RIP v1/v2, NHRP)
  • Network protocolsTCP, UDP, IPv4, IPv6, ICMP, NTP, DNS, HTTP, HTTPS, FTP, SMTP, SSL v3, TLS, ARP, VRRP, PPP, PPPoE, UPNP, SSH, DHCP, Telnet, SMPP, SMNP, MQTT, Wake On Lan (WOL)
  • VoIP passthrough supportH.323 and SIP-alg protocol NAT helpers, allowing proper routing of VoIP packets
  • Connection monitoringPing Reboot, Wget Reboot, Periodic Reboot, LCP and ICMP for link inspection
  • FirewallPort forward, traffic rules, custom rules
  • DHCPStatic and dynamic IP allocation, DHCP Relay, Relayd
  • QoS / Smart Queue Management (SQM)Traffic priority queuing by source/destination, service, protocol or port, WMM, 802.11e
  • DDNSSupported >25 service providers, others can be configured manually
  • Network backupWiFi WAN, Mobile, VRRP, Wired options, each of which can be used as an automatic Failover
  • Load balancingBalance Internet traffic over multiple WAN connections
  • HotspotInternal/external Radius server, captive portal, built in customizable landing page
  • SSHFSPossibility to mount remote file system via SSH protocol

    SECURITY
  • AuthenticationPre-shared key, digital certificates, X.509 certificates
  • FirewallPre-configured firewall rules can be enabled via WebUI, unlimited firewall configuration via CLI; DMZ; NAT; NAT-T
  • Attack preventionDDOS prevention (SYN flood protection, SSH attack prevention, HTTP/HTTPS attack prevention), port scan prevention (SYN-FIN, SYN-RST, X-mas, NULL flags, FIN scan attacks)
  • VLANPort and tag based VLAN separation
  • Mobile quota controlCustom data limits for SIM card
  • WEB filterBlacklist for blocking out unwanted websites, Whitelist for specifying allowed sites only
  • Access controlFlexible access control of TCP, UDP, ICMP packets, MAC address filter

VPN

  • OpenVPNMultiple clients and a server can run simultaneously, 12 encryption methods
  • OpenVPN EncryptionDES-CBC, RC2-CBC, DES-EDE-CBC, DES-EDE3-CBC, DESX-CBC, BF-CBC, RC2-40-CBC, CAST5-CBC, RC2-64-CBC, AES-128-CBC, AES-192-CBC, AES-256-CBC
  • IPsecIKEv1, IKEv2, with 5 encryption methods for IPsec (DES, 3DES, AES128, AES192, AES256)
  • GREGRE tunnel
  • PPTP, L2TPClient/Server instances can run simultaneously, L2TPv3 support
  • StunnelProxy designed to add TLS encryption functionality to existing clients and servers without any changes in the program’s code
  • DMVPNMethod of building scalable IPsec VPNs
  • SSTPSSTP client instance support
  • ZeroTierZeroTier VPN client support
  • WireGuardWireGuard VPN client and server support

MODBUS TCP SLAVE

  • ID rangeRespond to one ID in range [1;255] or any
  • Allow Remote AccessAllow access through WAN
  • Custom registersMODBUS TCP custom register block requests, which read/write to a file inside the router, and can be used to extend MODBUS TCP Slave functionality

MODBUS TCP MASTER

  • Supported functions01, 02, 03, 04, 05, 06, 15, 16
  • Supported data formats8 bit: INT, UINT; 16 bit: INT, UINT (MSB or LSB first); 32 bit: float, INT, UINT (ABCD (big-endian), DCBA (little-endian), CDAB, BADC)

MODBUS DATA TO SERVER

  • ProtocolHTTP(S), MQTT, Azure MQTT

MQTT GATEWAY

  • MQTT GatewayAllows sending commands and receiving data from MODBUS Master through MQTT broker

DNP3

  • Supported modesTCP Master, DNP3 Outstation

MONITORING & MANAGEMENT

  • WEB UIHTTP/HTTPS, status, configuration, FW update, CLI, troubleshoot, event log, system log, kernel log
  • FOTAFirmware update from server, automatic notification
  • SSHSSH (v1, v2)
  • SMSSMS status, SMS configuration, send/read SMS via HTTP POST/GET
  • CallReboot, Status, Mobile data on/off, Output on/off, answer/hang-up with a timer, WiFi on/off
  • TR-069OpenACS, EasyCwmp, ACSLite, tGem, LibreACS, GenieACS, FreeACS, LibCWMP, Friendly tech, AVSystem
  • MQTTMQTT Broker, MQTT publisher
  • SNMPSNMP (v1, v2, v3), SNMP Trap
  • JSON-RPCManagement API over HTTP/HTTPS
  • MODBUSMODBUS TCP status/control
  • RMSTeltonika Remote Management System (RMS)

IOT PLATFORMS

  • Cloud of ThingsAllows monitoring of: Device data, Mobile data, Network info, Availability
  • ThingWorxAllows monitoring of: WAN Type, WAN IP, Mobile Operator Name, Mobile Signal Strength, Mobile Network Type
  • CumulocityAllows monitoring of: Device Model, Revision and Serial Number, WAN Type and IP, Mobile Cell ID, ICCID, IMEI, Connection Type, Operator, Signal Strength
  • Azure IoT HubCan send device IP, Number of bytes send/received, Temperature, PIN count to Azure IoT Hub server, Mobile connection state, Network link state, IMEI, ICCID, Model, Manufacturer, Serial, Revision, IMSI, SIM State, PIN state, GSM signal, WCDMA RSCP, WCDMA EC/IO, LTE RSRP, LTE SINR, LTE RSRQ, CELL ID, Operator, Operator number, Connection type

SYSTEM CHARACTERISTICS

  • CPUMediatek MIPS 24Kc 580 MHz
  • RAM128 MB, DDR2
  • FLASH storage16 MB, SPI Flash

FIRMWARE / CONFIGURATION

  • WEB UIUpdate FW from file, check FW on server, configuration profiles, configuration backup, restore point
  • FOTAUpdate FW
  • RMSUpdate FW/configuration for multiple devices at once
  • Keep settingsUpdate FW without losing current configuration

FIRMWARE CUSTOMIZATION

  • RUT241 uses Teltonika Operating systemRutOS (OpenWrt based Linux OS)
  • Supported languagesBusybox shell, Lua, C, C++
  • Development toolsSDK package with build environment provided

INPUT / OUTPUT

  • Input
     1 x Digital Input, 0 – 6 V detected as logic low, 8 – 30 V detected as logic high
  • Output
     1 x Digital Output, Open collector output, max output 30 V, 300 mA
  • EventsEmail, RMS, SMS
  • I/O jugglerAllows to set certain I/O conditions to initiate event

POWER

  • Connector4-pin industrial DC power socket
  • Input voltage range9 – 30 VDC, reverse polarity protection; surge protection >31 VDC 10us max
  • PoE (passive)Passive PoE over spare pairs. Possibility to power up through LAN port, not compatible with IEEE802.3af, 802.3at and 802.3bt standards, Mode B, LAN1 Port, 9 – 50 VDC
  • Power consumption< 6.5 W Max

PHYSICAL INTERFACES

  • Ethernet2 x RJ45 ports, 10/100 Mbps
  • I/O’s
     1 x Digital Input, 1 x Digital Output on 4-pin power connector
  • Status LEDs3 x Connection type status LEDs, 5 x Connection strength LEDs, 2 x LAN status LEDs, 1 x Power LED
  • SIM1 x SIM slot (Mini SIM – 2FF), 1.8 V/3 V, external SIM holder
  • Power1 x 4-pin power connector
  • Antennas
     2 x SMA for LTE, 1 x RP-SMA for WiFi antenna connectors
  • ResetReboot/User default reset/Factory reset button

PHYSICAL SPECIFICATION

  • Casing materialAluminium housing, plastic panels
  • Dimensions (W x H x D)83 x 25 x 74 mm
  • Weight125 g
  • Mounting optionsBottom and sideways DIN rail mounting slots

OPERATING ENVIRONMENT

  • Operating temperature-40 °C to 75 °C
  • Operating humidity10% to 90% non-condensing
  • Ingress Protection RatingIP30

REGULATORY & TYPE APPROVALS

  • RegulatoryCE/RED, UKCA, CB

EMI IMMUNITY

  • IMMUNITY StandardsEN 301 489-1 V2.2.3 EN 301 489-17 V3.2.4 Final draft EN 301 489-52 V1.2.0 EN 55032:2015+A1:2020 EN 55035:2017+A11:2020 EN 61000-3-3:2013+A1:2019 EN IEC 61000-3-2:2019
  • ESDEN 61000-4-2:2009
  • RSEN 61000-4-3:2020
  • EFTEN 61000-4-4:2012
  • Surge immunity (AC Power Line)EN 61000-4-5:2014+A1:2017
  • CSEN 61000-4-6:2014
  • DIPEN IEC 61000-4-11:2020

RF

  • StandardsEN 300 328 V2.2.2, EN 301 511 V12.5.1, EN 301 908-1 V13.1.1, EN 301 908-2 V13.1.1, EN 301 908-13 V13.1.1

SAFETY

  • StandardsEN IEC 62311:2020, EN 50665:2017, EN IEC 62368-1:2020+A11:2020, IEC 62368-1:2018

TELTONIKA RUT241 OVERVIEW

Summary

The Overview page contains various information summaries and shortcuts to other pages. It is also the homepage of the WebUI. This chapter is an overview of the Overview page for RUT241 routers. If you’re having trouble finding this page or some of the parameters described here on your device’s WebUI, you should turn on “Advanced WebUI” mode. You can do that by clicking the “Basic” button under “Mode”, which is located at the top-right corner of the WebUI.

Networking rut2m manual webui basic advanced mode.gif

Overview

The Overview page contains widgets that display the status of various systems related to the device. The figure below is an example of the Overview page:

Networking rutos manual overview 1 1 v2.png

Mobile widget


The Mobile widget displays information related to the mobile connection and the current signal strength (). Each filled-up bar represents a different RSSI value:

BarsSignal Strength Value / RSSI (In DBm)
0≤ -111
1-110 to -97
2-96 to -82
3-81 to -67
4-66 to -52
5≥ -51

The same calculation principle applies to the Signal strength LEDs located on your device. You can find more information on signal strength values and different measurements here.

Widget button: Info


The Info () button is located next to the name of some widgets. Clicking the Info button redirects the user to a status page related to the widget’s displayed information. For example, clicking the Info button on the System widget would redirect the user to the Status → System page:

Networking rutx11 manual overview widget button info action v1.png

Widget button: Settings


The Settings button is located next to the name of some widgets. Clicking the Settings button redirects the user to a configuration page related to the widget’s displayed information. For example, clicking the Info button on the Mobile widget would redirect the user to the Network → Interface →LAN Configuration page:

Networking rutos manual overview widget button settings v1.png