Copper Ethernet has a hard limit: 100 meters per segment. Beyond that, signal degrades. Data drops. It’s not a suggestion—it’s physics, defined by the IEEE 802.3 Ethernet standard .
The market for fiber optic media converters is big. In 2024 it was worth 2.1 to 2.5 billion dollars. It will keep growing at a rate of 8 to 10 percent until 2030. There are three reasons for this growth. People need to extend their networks beyond the limits of copper. They need to stop interference. They need to connect copper equipment to new fiber networks.
A fiber media converter can solve these problems. It takes the signal from a copper cable. Changes it into light pulses that can travel over fiber optic cable. The copper device does not know it is sending signals to a fiber network. The fiber network does not know the signal came from a copper device.
This guide explains when you actually need a converter, how to choose the right type, and what makes industrial‑grade units different from office‑grade gear.
First, the Problem Copper Has
Copper Ethernet (the blue cables with RJ45 plugs) has a hard limit: 100 meters. After that, signal degrades. Data drops. It’s not a suggestion—it’s physics.
You can add switches to make the distance longer.. Switches need electricity. They can also fail.. They cost money.
Fiber optics do not have this issue. Single-mode fiber can go 10, 20 or 40 kilometers easily.
Your current equipment likely has copper ports. Switches, cameras and PLCs are made for RJ45. You cannot plug fiber into them directly.
That’s where the converter comes in to help.
What a Fiber Media Converter Does
A fiber media converter is a box. It has a copper port, on one side which’s usually an RJ45 port. The other side has a fiber port, which can be SC, ST or LC. This device takes signals from the copper side and converts them into light pulses. These light pulses are then sent down the fiber cable.
A fiber media converter helps connect copper-based devices to fiber-based networks. It does this by converting the signals into light pulses. The light pulses are then transmitted over the fiber cable.
The device that is connected to the copper side does not know that it is talking to fiber. The other device that is connected to the fiber side does not know that the signal started from copper. The converter is what does the translation, for the copper and the fiber. It makes the copper and the fiber work together.
When You Actually Need One
Scenario 1: Distance Exceeds 100 Meters
This is the common reason for something like this to happen. You see a security camera is usually placed at the end of a parking lot. Then there is a pump station that’s about half a kilometer away from the security camera. On the side of things there is a weather station that is located on the far side of a field, which is also pretty far away, from the security camera and the pump station. The security camera is still the thing that people are talking about.
So we need to put a converter at each end of the connection. We will use copper cable to connect the switch to the converter. Then we will use fiber optic cable to connect the two converters to each other. After that we will use copper cable again to connect the converter to the camera. The thing is the camera is going to think that it is 10 meters away from the switch even though that is not really the case, with the camera and the switch. We are using converters and different types of cable like copper and fiber to make this connection work for the camera and the switch.
What you need: Two fiber media converters (one for each end), fiber cable between them.
Scenario 2: Electrical Interference
Motors and VFDs and high-voltage lines they all make a lot of noise. The copper in the wires is like an antenna that catches all that noise. This noise messes up the data that is being sent. Sometimes the communication. Sometimes it does not work at all because of this noise, in the Motors and VFDs and high-voltage lines.
Fiber is immune. No metal, no antenna, no noise.
If you have equipment in a noisy environment, fiber isolates it completely.
What you need: Converters at both ends, same as distance scenario. The difference is the reason.
Scenario 3: Mixing Old and New
You’re upgrading to fiber gradually. The new backbone is fiber, but the switches you already have are copper. Replacing them all at once is expensive.
To solve this problem you can put a converter, between the fiber backbone and each copper switch.
This way the switches stay where they are and the fiber network upgrades. The fiber network and the copper switches will work together with the help of the converters.
The fiber backbone and the copper switches will be connected with these converters.
What you need: One converter per copper switch you want to connect to fiber.
Scenario 4: Power Over Long Distances (PoE)
Some devices need power and data, over the cable. This includes cameras, access points and sensors. Copper cables can provide power using PoE.
If you need to power a device at the far end of a long run, use a PoE fiber media converter. It takes fiber in, sends copper+power out.
What you need: We need a kind of converter that can handle power, over ethernet, which is called a PoE-capable fiber media converter and we will put this at the far end. At the end we might need a regular converter, just a normal one.
Scenario 5: Harsh Environments
Outdoor cabinets and factory floors and substations are really places, for equipment. The temperature is always changing. There is dust and moisture everywhere.. The vibration is constant.
Regular converters just do not last in these conditions. That is why we need industrial-grade converters. These industrial-grade converters are made to withstand all this.
What you need: Industrial media converters with wide temperature range (-40°C to 85°C), metal cases, and terminal block power.
Types of Fiber Media Converters
(Converter Types and When to Use Them)
| Type | What It Does | When to Use |
|---|---|---|
| 10/100M Ethernet to Fiber | Converts standard Fast Ethernet to fiber | Most common. For cameras, access points, basic networking. |
| Gigabit Ethernet to Fiber | For 1000Mbps speeds | When you need more bandwidth. Multiple cameras, backbone links. |
| PoE Fiber Converter | Provides power over copper on the output side | Powering remote cameras or access points without local power. |
| Serial to Fiber | Converts RS232/485 to fiber | Extending serial connections (PLC, meter, controller) over long distances. |
| Industrial Grade | Wide temp, metal case, terminal power | Factories, outdoors, substations, anywhere harsh. |
| Managed Converter | Can be monitored and configured remotely | When you need to know what’s happening at the far end. |
What About Single-Mode and Multi-Mode?
Two types of fiber:
- Multi-mode: Shorter distances (up to 2km), cheaper optics. Good for inside buildings, campuses.
- Single-mode: Long distances (10km+), more expensive optics. Good for between buildings, long runs.
Most factories use single-mode fiber. This is because it can handle needs. It also works over longer distances. Single-mode fiber is a choice, for many industrial uses.
You have to make sure your converter is the kind, for the fiber you are using. If you have a converter that is made for -mode fiber it will not work with single-mode fiber.. The other way around is also true a converter made for single-mode fiber will not work with multi-mode fiber. You really need to get a converter that matches the type of fiber you have whether it is single-mode fiber or multi-mode fiber.
Industrial vs. Office‑Grade Converters
| Feature | Office Grade | Industrial Grade |
|---|---|---|
| Operating temp | 0°C to 40°C | –40°C to 85°C |
| Enclosure | Plastic | Metal |
| Power input | 5V USB or 12V wall wart | 9–24V DC terminal |
| Mounting | Desktop | DIN rail |
| Protection | None | Surge, ESD, isolation |
In a control panel that reaches 60°C in summer, an office‑grade converter may overheat and fail. In an environment with motors and drives, lack of shielding can cause data corruption.
How to Choose: A Decision Framework
| If you need to… | Choose |
|---|---|
| Extend Ethernet over long distance | 10/100M or Gigabit Ethernet to Fiber converter |
| Power a remote device (camera, AP) | PoE fiber converter |
| Connect a serial device (PLC, meter) | Serial to Fiber converter (plug‑and‑play or TCP/IP) |
| Monitor the link remotely | Managed converter |
| Install in a harsh environment | Industrial grade (–40°C to 85°C, metal case, DIN rail) |
Three Real Products, Three Different Jobs
Valtoris makes three fiber media converters. Each one does a different thing.
VT-FB800: Ethernet to Fiber
What it does: Converts 10/100M Ethernet to fiber. Single-mode, single-fiber SC connector, up to 20km.
What’s worth noting:
- Single-fiber design: Uses one fiber instead of two. Saves money on long runs.
- Wide power input: 9-24V DC. Works with industrial 24V panels directly.
- Temperature range: -40°C to 85°C. Not just “industrial” on paper.
- A and B ends: Comes in matched pairs. One end transmits on 1310nm, receives on 1550nm. The other end swaps them.
One thing to know: You have to use A and B ends together. Two A ends won’t work. Order them as pairs.
Best for: Extending Ethernet networks—cameras, switches, access points—over long distances.
Which One Do You Need?
| If you need to… | Choose this |
|---|---|
| Extend Ethernet over long distance | VT-FB800 |
| Connect a serial device (PLC, meter) with no config | VT-FB820 |
| Connect a serial device and access it over IP | VT-FB810 |
All three are industrial grade: -40°C to 85°C, 9-24V DC power, metal case.
Installation in Two Minutes
- Place converters at both ends.
- Connect copper (or serial) to one side.
- Connect fiber between them.
- Apply power (9-24V DC).
- Done.
No configuration. No IP addresses to set. No software to install. The converters just work.
Common Questions
Q: Can I use one converter by itself?
No. They work in pairs—one at each end of the fiber.
Q: What’s the difference between A and B ends?
They transmit and receive on different wavelengths so one fiber can carry both directions. A end: TX 1310nm, RX 1550nm. B end: the opposite.
Q: How far can I go?
VT-FB800 and VT-FB820 are rated for 20km with single-mode fiber. Longer distances possible with different optics.
Q: Does it work with any fiber?
Use single-mode fiber with SC connectors. Multi-mode fiber won’t work.
Q: Do I need managed or unmanaged?
Unmanaged switches are really simple to use. You just plug them in. They work. Managed switches are a bit more complicated because they let you check on the connection, from else. You should choose a managed switch if you need to know away when the connection is lost. If you do not need to know that then an unmanaged switch is fine.
Who Searches for This?
- Facility managers extending networks to outbuildings
- Security integrators running cameras across large sites
- Industrial electricians connecting remote equipment
- IT people dealing with distance limits
- Engineers designing systems with long cable runs
They search because they hit the 100-meter wall and need a way through.
Bottom Line
Fiber media converters exist for one reason: copper doesn’t go far enough.
If you need to:
- Reach beyond 100 meters
- Get rid of electrical interference
- Connect old copper gear to new fiber
- Power a remote device over long distance
- Survive harsh conditions
…then you need one.
Valtoris makes three:
- VT-FB810 for serial with IP networking
- VT-FB800 for Ethernet
- VT-FB820 for serial (plug and play)
If your situation matches the scenarios above, one of them will do the job.
If not, at least now you know what to look for.
