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Media Converters Application Tips

Time:2019-03-08 Source:UTEPO

Due to the maximum transmission distance of the network cable is 100 meters, it is necessary to use media converters or Ethernet repeaters for the long-distance transmission. The media converters are commonly used in network environments where Ethernet cables cannot be covered or the optical fiber must be used to extend the transmission distance.

How to use a media converter?

The transmission distance of optical fiber is relatively long, generally speaking, the transmission distance of single-mode optical fiber is more than 10km, while the transmission distance of multi-mode optical fiber is up to 2km. In the implement of optical fiber, it often uses the media converters, of which optical signal is input to optical port and electric signal is output from RJ45 port, and the reverse is also true.

The process consists of converting electrical signals into optical signals, transmitting them through optical fibers, converting optical signals into electrical signals at the other end which is connecting to routers, switches, and other devices.

Generally, the media converters are used in pairs. For example, if there are different brands media converters inside the computer room, you must use them in pairs to build your own LAN.

Same operation with Ethernet switches, the media converters are featuring with plug and play, and no extra configuration needed. Please connect the right position for receiving cable and transmitting cable.

LED Indicator of Media Converter

There usually are 6 indicators in media converters with their specific significance, of which you could preliminarily screened and judged some common faults by the working state.

Take MC2-GS (UTEPO Gigabit Media Converter) as an example, the product is equipped with 6 LED indicators. You can judge the faults preliminarily according to the indicators.

- If the media converters operate well, the PWR indicator should be solid ON.

- The FX/ACT and TX/ACT indicator should be solid ON or Blink.

- If FX/ACT and TX/ACT indicator is OFF, please check the related wiring.

- The ON/OFF status of FDX, 1000M and 100M indicator have no influence on the performance of media converters.

Fault Analysis on Media Converters

There are many kinds of media converters, but the fault analysis methods are basically the same. In summary, the faults are as follows:

1. PWR indicator is OFF.

- Power failure.

2. FX/ACT indicator is OFF.

The failure may be as follows:

A. Check whether the optical fiber wiring is broken.

B. Check whether loss of the optical fiber wiring is too large, which is beyond the equipment available range.

C. Check that the optical fiber interface is properly connected, the TX of A is connected to the RX of B, and the TX of B is connected to the RX of A.

D. Check whether the fiber optic connector is properly inserted into the device interface, whether the patch cable type matches the device interface, whether the device type matches the fiber optic, and whether the transmission distances match with each other.

3. TX/ACT indicator is OFF.

The failure may be as follows:

A. Check whether the wiring is broken.

B. Check whether the connection type matches:

- It uses crossover wired cables for the network card and the router etc.

- It uses straight-through wired cables for switch, hub etc.

C. Check the transmission rates match with each other.

Network packet losses are serious.

4. The failure may be as follows:

A. The duplex modes (RJ45 ports of media converter and network device or RJ45 ports of network devices in both ends.) don’t match.

B. Test the twisted pair and RJ45 jack.

C. Fiber optic cable connection problems

- Whether the patch cable is aligned with the device interface.

- Whether the tail fiber, patch cable and the coupler are matched.

5. After the fiber optic transceiver is connected, the two ends cannot communicate.

A. The fiber optic cables are connected inversely. (this problem does not exist in single-fiber equipment).

B. The RJ45 port is not connected to the external device correctly (Straight-through wired/ Crossover wired).

The optical fiber ports (ceramic core) do not match, and this fault is mainly reflected in the 100M media converters with photoelectric mutual control function. For example, the tail fiber of APC core plug is connected to the media converter of PC core plug, and it will not be able to communicate normally, while there is no influence on the connection of non-photoelectric mutual control media converter.

6. Unstable transmission

A. It may be caused by the large attenuation of optical path.

- You can measure the optical power of the receiver by an optical power meter. If the tested optical power is beyond the range of receiving agility in 1-2db, it can be basically judged as an optical path fault.

B. It may be caused by the fault of the switch connected to the media converter.

- Replace the switch to a PC and connect to the media converters in both ends, and do the PING test for both ends. If the tested data are unstable, it can be basically judged as the switch fault.

C. It may be caused by the fault of media converter.

- Connect the both ends of media converter to PCs (Do not go through the switch.), do the PING test for both ends, and the test is ok. Then send a big file (Size over 100M) from one side to the other side, and check the speed. If the speed is very slow (Over 15 minutes to finish the transmission for over 200M file.), it can be basically judged as the media converter fault.

7. Communication fails after a period of time, and returns to normal after restart.

This phenomenon is generally caused by the switch. The switch will perform CRC error detection and length verification on all the received data, and if the wrong packet is found, it will be discarded, while the correct packet will be forwarded directly.

During this process, it may not be able to detect some wrong packets, therefore those wrong packets wont be forwarded or discarded, and are kept in the buffer of the switch. Until the buffer is full, it would freeze the switch.

8. Test method for media converter

A. Near-end test

- Connect PCs for both ends and do PING test, If the testing result is failed, the media converter is fault.

B. Remote-end test

- Connect PCs for both ends and do PING test, If the testing result is failed, check whether the optical connection is normal and whether the transmitting and receiving power of the optical transceiver is within the allowed range. If the PING is successful, the optical connection is normal. It can be determined the fault is on the switch.


1. Single-mode / Multi-Mode for Optical Port

The single-mode media converter can work under both single-mode fiber and multi-mode fiber, while multi-mode media converter can only work under multi-mode fiber. Although the single-mode device could be used with multi-mode fiber for short-distance transmission, we suggest to use the corresponding types of devices to avoid any packet losing.

2. Distinguish between single fiber device and dual fiber device.

The dual fiber device is equipped with one transmitting port (TX) and one receiving port (RX). You may have the trouble with connection for RT and RX. While the single fiber device is equipped with just one port for both transmitting and receiving, it is easy to use and save the uses of fiber optics, reducing the cost of the whole project.

3. Reliability of the media converter.

- Environment Temperature

There would be high heat produced during the operation of the media converter. If the temperature is too high, the device could not work well. The UTEPO MC2-FS & MC2-GS allow the highest working temperature range for - 20℃ ~ + 60℃, which is reducing the the possibility of unexpected failure for long-term operation of equipment.

- Anti-surge

The cameras of the monitoring system are mostly installed in the outdoor environment, and the equipment or cables are at high risk of being damaged by direct lightning. Due to sensitivity to lightning over voltage, power system operating over voltage, electrostatic discharge and other electromagnetic interference, it easily leads to equipment damage, or causes paralysis of the entire monitoring system.

UTEPO MC2-FS & MC2-GS are equipped TSS discharge tube, which allows 6KV surge immunity, and effectively reduce the maintenance cost caused by lightning damage.

4. Full duplex and half duplex

Some media converters in the market only support full duplex. If media converter connecting to only half-duplex supported SWITCH or HUB of other brands, it will certainly cause the conflict and packet loss.



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