Hello, we are using a OTD500 for about a month now. We use it as an internet failover (second WAN). When connected to the OTD500 the download speeds are very good via 5G (>200mbps). But the upload speeds are terrible (<3Mbps). Even when we are directly connected from a computer (so no router in between) the speeds are bad. When performing a speedtest through the webinterface the download speed is >200mbps and the upload speed is >30Mbps. These values are the expected speeds. So what is causing the bad upload speed when connected to the OTD500?
Apologies for the delay. Could you please confirm what server was selected when performing the speed test via the OTD500 WebUI? Was it the same server as the one used when testing from your computer through the Speedtest page?
If not, try to manually select the same server on both tests —or, alternatively, test with a different nearby server (preferably one from your provider) to see if the issue persists.
It’s possible that at the time of testing, the auto-selected server on Speedtest had a heavier load or higher latency on the upload side, which could explain the discrepancy.
We have indeed performed multiple speed tests at different times, using various nearby servers, including those recommended by our provider. The results from the OTD500 WebUI speed tests consistently show both download and upload speeds meeting expectations.
However, the issue remains that when the OTD500 is connected to a router or directly to a laptop, the download speeds are generally fine, but the upload speeds are significantly reduced — typically around 4 Mbps, far below the expected performance.
This discrepancy between the device’s own speed test and real-world upload performance through connected equipment is the core of our problem.
We would appreciate any further insights or troubleshooting steps you could provide to help resolve this upload speed limitation when using the OTD500 as a failover or primary connection.
Could you please confirm whether you’re using the router in bridge mode when connecting the OTD500?
Additionally, please make sure the device firmware is up to date, ideally running the latest 7.15 version. If not, I’d recommend updating and letting me know if this brings any improvements to the upload performance.
Yes, the OTD500 has been tested in Bridge, NAT, and Passthrough modes — all with similar results: download is fine, but upload remains significantly limited when connected through a router or directly via Ethernet. However, when running a speed test directly from the WebUI of the OTD500 itself, upload is as expected.
The device is running the latest firmware (OTD5_R_00.07.15, build date 2025-06-04), and the internal modem firmware is also up to date (RG520NEBDCR03A04M4G_01.200.01.200).
Relevant troubleshooting has already been performed in both the device and modem settings, but the issue persists across different setups and hardware.
Given the specific nature of the problem, would there be any way to escalate this for direct technical support from Teltonika? We’d really appreciate more in-depth assistance at this point.
Thank you for the update. I believe, to assist you effectively, we’ll need to continue this process privately. You should find a support request form in the inbox of the email address you used for your forum registration. Kindly fill out the form, and please reference Ticket ID: 13636 when submitting it. Once the form is completed, we’ll contact you directly via email to investigate the issue in detail and help work towards a solution.
