Signal Bars vs. RSSI: Know the real strength
#2025, #remotemanagement, #connectivity
Signal bars may look simple, but they don’t tell the whole story. In the IoT world, knowing your connection’s quality is just as important as establishing it.
At Teltonika, we deliver not only powerful industrial networking devices but also the insights you need to use them effectively. That starts with understanding mobile signal metrics.
Signal values vary by modem, carrier, and environment—and a strong signal doesn’t always mean fast data. Network congestion, like tower load, weather, proximity to the cellular tower, also impacts performance.
While there is no black-and-white definition of a successful connection, metrics such as RSSI, RSRP signal strength, and SINR offer a clearer picture. For example, even with a strong RSSI of −51 dBm, data speeds can suffer if the network is overloaded.
For professionals, accuracy matters. That’s why we focus on real signal metrics—not just the bars . Let’s break it down by generation.
2G: RSSI LEVEL MEASURING
In 2G networks, the primary signal measurement is the Received Signal Strength Indicator (RSSI). Its value relates to the signal strength of the cellular signal from the tower to the modem.
To check the 2G signal strength value of your RUT device, log in to your router’s WebUI and navigate to Status → Network → Mobile.
While RSSI offers a basic overview, it doesn’t reflect the quality of the signal. DBm meaning refers to power measured in milliwatts, commonly used to assess telecom signal strength. Still, it’s your main reference point when working with 2G technology. If your operations depend on consistent 2G coverage, aim for the best mobile signal strength above − -70 dBm whenever possible.
3G: COMBINING RSSI, EC/IO and RSCP
3G networks use three indicators: RSSI, Ec/Io, RSCP. RSSI works similarly to 2G, but Ec/Io adds signal quality by measuring interference. RSCP tells you how strong the signal is after it's been processed by the network.
To check the 3G signal strength values of your RUT device, log in to your router's WebUI and go to the Status -> Network -> Mobile window:
When optimising a 3G setup, don’t rely solely on Received Signal Strength Indicator (RSSI). A strong RSCP combined with a clean Ec/Io ensures low latency, stable connections, and consistent data throughput.
4G and 5G: RSSI, RSRP, RSRQ, AND SINR TAKE THE STAGE
For 4G and 5G, signal strength and quality are measured using four main indicators. Received Signal Strength Indicator (RSSI) shows total 4G and 5G signal strength but includes noise. RSRP measures the strength of the useful signal. RSRQ shows how clean the signal is, like Ec/Io in 3G. SINR compares your signal to any interference—higher SINR means faster, more stable internet.
To check the 4G/5G RSSI signal strength values of your RUT device, log in to your router's WebUI and go to the Status -> Network -> Mobile window:
Received signal strength indicator (RSSI) in LTE is a combined measure of noise, signal, and interference. It’s calculated as:
Received signal strength indicator (RSSI) = noise + serving cell power + interference power. For example, a 4G LTE modem might show:
RSSI = -68 dBm /RSRP = -56 dBm / RSRQ = -16 dB/ SINR = -1.8 dB
These numbers reveal poor signal quality. This could be caused by distance from the cell tower or interference (e.g., buildings or obstacles blocking the signal).
OTHER METHODS TO CHECK SIGNAL QUALITY
WebUI: navigate to Status → Network → Mobile. The Mobile Information section displays key parameters depending on the network type: for LTE – RSSI, RSRP, RSRQ, and SINR; for 3G – RSSI, EC/IO, and RSCP; and for 2G – only RSSI.
Router LEDs: check the Signal Strength LEDs on the router's front panel. While these do not show exact values, they represent RSSI strength in bars, much like a mobile phone.
ADVANCED MEASUREMENT
To get the most detailed information about your signal quality values, you can use gsmctl commands when logged in via CLI or SSH.
These commands are designed to communicate directly with the router's modem. When a user sends a gsmctl command, the router converts it into an AT command and forwards it to the modem. The modem responds with raw data, which the router interprets and returns to you in readable form.
Key gsmctl command for signal quality:
· gsmctl -q – returns current signal values
This method is ideal for advanced diagnostics, automation, or when working in headless setups where WebUI access isn't practical. Whether you're performing remote monitoring or scripting your deployments, gsmctl provides unmatched visibility into signal behaviour.
You can use CLI (Command Line Interface) which allows you to enter and execute commands into the router's terminal. CLI can be found in the System section (System -> Maintenance -> CLI).
The default Username for logging into CLI is root and the password is your router's password. Once you've logged in you should be greeted by a window like this:
The command should be as follows:
WHY UNDERSTANDING SIGNAL MATTERS
Understanding RSSI signal strength dBm meaning, is more than a technical detail—it’s critical for reliable, long-term operation. Signal drops, interference, and slow speeds can compromise your operation success.
With Teltonika devices, you can monitor these values directly from the WebUI or Remote Management System (RMS). This means you can verify the best mobile signal strength without leaving your desk—or optimise installations onsite with real-time feedback.
GENERAL TIPS ON IMPROVING SIGNAL:
1. Position the antenna of your mobile router in the best location to receive the strongest signal. This may involve moving it closer to a window or outside the building.
2. Obstructions like buildings, trees, and even walls can interfere with the cellular signal. Try to position your mobile router in an area with the least amount of interference.
3. Ensure the antenna connections on your router are tight and secure. Loose connections can degrade the signal.
4. If you've exhausted all other options, it may be worth considering switching to a network provider with better coverage in your area.
THE IMPORTANCE OF STRENGTH
From smart cities to industrial automation, reliable connectivity starts with understanding your signal metrics. Knowing what received signal strength indicator (RSSI) and other values truly mean, helps you make informed decisions and ensures your setup performs at its best.
At Teltonika, we go beyond hardware—we empower you with the insights and tools to turn every connection into a success. Ready to get started on your next project? Click the “Contact us” button below—we’re here to help.
