The use of optical fiber transceivers in weak current projects is very common, so how do we choose optical fiber transceivers in engineering projects? When the fiber optic transceiver fails, how to maintain it?
1.What is a fiber optic transceiver?
The optical fiber transceiver is also called a photoelectric converter, which is an Ethernet transmission media conversion unit that exchanges short-distance twisted pair electrical signals and long-distance optical signals.
The different viewing angles make people have different understandings of fiber optic transceivers, such as single 10M, 100M fiber optic transceivers, 10/100M adaptive fiber optic transceivers and 1000M fiber optic transceivers according to the transmission rate; they are divided into work methods. Fiber optic transceivers working at the physical layer and fiber optic transceivers working at the data link layer; from a structural point of view, they are divided into desktop (stand-alone) fiber optic transceivers and rack-mounted fiber optic transceivers; according to the difference in access fiber There are two names for multi-mode optical fiber transceiver and single-mode optical fiber transceiver.
In addition, there are single-fiber optic transceivers and dual-fiber optic transceivers, built-in power fiber optic transceivers and external power fiber optic transceivers, as well as managed fiber optic transceivers and unmanaged fiber optic transceivers. Fiber optic transceivers break the 100-meter limitation of Ethernet cables in data transmission, relying on high-performance switching chips and large-capacity buffers, while truly achieving non-blocking transmission and switching performance, it also provides balanced traffic, isolation of conflicts and Error detection and other functions ensure high security and stability during data transmission.
2.The application of optical fiber transceiver
In essence, the optical fiber transceiver only completes the data conversion between different media, which can realize the connection between two switches or computers within 0-100Km, but the actual application has more expansion.
1. Realize the interconnection between switches.
2.Realize the interconnection between the switch and the computer.
3.Realize the interconnection between computers.
4.Transmission relay: When the actual transmission distance exceeds the nominal transmission distance of the transceiver, especially when the actual transmission distance exceeds 100Km, if the site conditions permit, two transceivers are used for back-to-back relay. Very cost-effective solution.
5. Single-multimode conversion: When single-multimode fiber connection is needed between networks, one multi-mode transceiver and one single-mode transceiver can be connected back to back to solve the problem of single-multimode fiber conversion.
6. Wavelength division multiplexing transmission: When the long-distance optical cable resources are insufficient, in order to increase the utilization rate of the optical cable and reduce the cost, the transceiver and the wavelength division multiplexer can be used together to transmit the two channels of information on the same pair of optical fibers.
3.The use of optical fiber transceiver
In the introduction, we know that there are many different categories of fiber optic transceivers, but in actual use, most of the attention is paid to the categories that are distinguished by different fiber connectors: SC connector fiber optic transceiver and ST connector fiber optic transceiver.
When using fiber optic transceivers to connect different devices, you must pay attention to the different ports used.
1. Connection of fiber optic transceiver to 100BASE-TX equipment (switch, hub):
Confirm that the length of the twisted pair cable does not exceed 100 meters;
Connect one end of the twisted pair to the RJ-45 port (Uplink port) of the fiber optic transceiver, and the other end to the RJ-45 port (common port) of the 100BASE-TX device (switch, hub).
2. Connection of fiber optic transceiver to 100BASE-TX equipment (network card):
Confirm that the length of the twisted pair cable does not exceed 100 meters;
Connect one end of the twisted pair to the RJ-45 port (100BASE-TX port) of the fiber optic transceiver, and the other end to the RJ-45 port of the network card.
3. Connection of fiber optic transceiver to 100BASE-FX:
Confirm that the length of the optical fiber does not exceed the distance range provided by the equipment;
One end of the fiber is connected to the SC/ST connector of the fiber optic transceiver, and the other end is connected to the SC/ST connector of the 100BASE-FX device.
Another thing that needs to be added is that many users think when using fiber optic transceivers: as long as the length of the fiber is within the maximum distance supported by single-mode fiber or multi-mode fiber, it can be used normally. In fact, this is a wrong understanding. This understanding is correct only when the connected devices are full-duplex devices. When there are half-duplex devices, the transmission distance of the optical fiber is limited.
4.The principle of optical fiber transceiver purchase
As a regional network connector device, the optical fiber transceiver is its main task is how to seamlessly connect the two parties’ data. Therefore, we must consider its compatibility with the surrounding environment, as well as the stability and reliability of its own products, on the contrary: no matter how low the price is, it cannot be used!
1. Does it support full duplex and half duplex?
Some chips on the market can only use the full-duplex environment at present, and cannot support half-duplex. If they are connected to other brands of switches (SWITCH) or hubs (HUB), and it uses half-duplex mode, it will definitely cause Serious conflict and loss.
2. Have you tested the connection with other optical transceivers?
At present, there are more and more fiber optic transceivers on the market. If the compatibility of transceivers of different brands has not been tested beforehand, it will also cause packet loss, long transmission time, and sudden speed and slowness.
3. Is there a safety device to prevent packet loss?
In order to reduce costs, some manufacturers use Register data transmission mode when manufacturing fiber optic transceivers. The biggest disadvantage of this method is instability and packet loss during transmission. The best is to use buffer circuit design. Can safely avoid data packet loss.
4. Temperature adaptability?
The fiber optic transceiver itself will generate high heat when it is used. When the temperature is too high (generally not greater than 85°C), does the fiber optic transceiver work normally? What is the maximum allowable operating temperature? For a device that needs long-term operation, this item is worth our attention!
5.Does it comply with the IEEE802.3u standard?
If the optical fiber transceiver meets the IEEE802.3 standard, that is, the delay and time is controlled at 46bit, if it exceeds 46bit, it means that the transmission distance of the optical fiber transceiver will be shortened! !
Five, common fault solutions for optical fiber transceivers
1. Power light does not light up
electricity failure
2.Link light does not light up
The fault may be as follows:
(a) Check whether the optical fiber line is open
(b) Check whether the loss of the optical fiber line is too large, which exceeds the receiving range of the equipment
(c) Check whether the optical fiber interface is connected correctly, the local TX is connected with the remote RX, and the remote TX is connected with the local RX.
(d) Check whether the optical fiber connector is properly inserted into the device interface, whether the jumper type matches the device interface, whether the device type matches the optical fiber, and whether the transmission length of the device matches the distance.
3. Circuit Link light does not light up
The fault may be as follows:
(a) Check whether the network cable is open
(b) Check whether the connection type matches: network cards and routers and other equipment use crossover cables, and switches, hubs and other equipment use straight-through cables.
(c) Check whether the transmission rate of the device matches
4. Serious network packet loss
The possible failures are as follows:
(1) The electrical port of the transceiver and the network device interface, or the duplex mode of the device interface at both ends do not match.
(2) There is a problem with the twisted pair cable and the RJ-45 head, check it
(3) The fiber connection problem, whether the jumper is aligned with the device interface, whether the pigtail matches the jumper and the coupler type, etc.
(4) Whether the optical fiber line loss exceeds the equipment receiving sensitivity.
5. The two ends cannot communicate after the fiber optic transceiver is connected
(1). The fiber connection is reversed, and the fiber connected to TX and RX are swapped
(2). The RJ45 interface and the external device are not connected correctly (pay attention to straight-through and splicing). The optical fiber interface (ceramic ferrule) does not match. This fault is mainly reflected in the 100M transceiver with photoelectric mutual control function, such as the APC ferrule. When the pigtail is connected to the transceiver of the PC ferrule, it will not be able to communicate normally, but it will have no effect if it is connected to a non-optical transceiver.