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Introduction of Patch Cord

DATE:2022-09-16   VISITS:157

Introduction of Connector 

Types and Testing Methods of Patch Cord 

   Patch cord is a metal connecting wire used to connect the two electronic components of a circuit board. Due to different manufacturers and different usage requirements, the material and the wire thickness of the patch cord are accordingly different. 

   Most patch cords are used for equal-potential voltage transmission, and some are used to protect the reference voltage of the circuit. The outer sheath material can be PVC, LSZH or other materials. Some of the materials meet the requirements of OFNR and OFNP flame retardant grades. The length of the patch cord can also be customized according to requirements. In order to ensure the accuracy of data transmission, the optical fiber should not be bent and looped excessively during use, which will increase the attenuation of light during transmission. 

   Fiber patch cord products are generally widely used in: communication room, fiber-to-the-home, local area network, fiber-optic sensors, fiber-optic communication systems, fiber-optic connection transmission equipment, etc. It is suitable for cable television network, telecommunication network, computer optical fiber network and optical test equipment. It plays a vital role in fiber optic cable and communication transmission. 

About specifications of fiber patch cords, first of all, let's take a look at the fiber 

optic patch cord connector. The connector of patch cord is a must-consider issue 

when purchasing fiber optic patch cords from the manufacturer. Understanding 

the difference of various connector types can help you find out the products you 

need faster. 



 If classified by connector type, The common connector types of fiber patch cord are FC, ST, SC, PC, APC, and LC. Different ends fiber patch cord with FC connectors are mostly used on MDF, while with SC connectors are mostly used on circuit switch. In addition, there are various forms of optical fiber connector types such as MTRJ, MPO, MU, SMA, FDDI, E2000, D4, etc. 

  And what does FCSTSCLCMTRJAPCUPC represent in the fiber patch cord?

1. FC, ST, SC, LC, MTRJ are different physical interface connection methods. 

2. FC is a circular spiral mouth. 

3. ST is a round 45 degree bayonet. 

4. SC is a square socket. 

5. LC and MTRJ are small ferrule connectors, which are rarely used in China, but are provided on some imported equipment. 

6. PC, APC, UPC represent the front-end surface structure of the ceramic ferrule. 

7. PC is a spherical structure, APC is an 8-degree angle structure, and UPC is a hyperplane structure.

   According to different connector combinations, there are three main types of fiber patch cord: ST-ST, SC-SC and ST-SC. If classified by the type of fiber, there are mainly two types: single-mode fiber and multi-mode fiber. The specifications of the patch cord length are 0.5m, 1m, 2m, 3m, 5m, 10m and so on. According to the cable outer sheath material, it can be divided into ordinary type, ordinary flame-retardant type, low-smoke halogen-free type (LZSH), low-smoke halogen-free flame-retardant type, etc.


   FC type fiber patch cord

   For FC type fiber patch cord, the external reinforcement method is a metal sleeve, and the fastening method adopts a turnbuckle. There is a nut screwed to the adapter, which makes it to be reliable and dust-proof, while the disadvantage is it will take a lightly longer time to install. FC type patch cord is generally used on the ODF side (the most used on the patch panel, and also mostly used for optical transceivers).   

The connector on the ODF side generally uses FC connectors. FC is a metal connector, but ODF does not have high temperature problems. At the same time, metal connector is more durable as it has a better performance in multiple plug and unplug than that of plastic, and the maintenance of ODF pigtails is more than that of optical board pigtails.

SC type fiber patch cord 

   "SC" indicates that the pigtail connector is an SC connector. The optical interface on the side of transmission equipment in the in dustry generally uses an SC connector. The SC connector is made of engineering plastic,which is resistant to high temperature and is not easy to oxidize.Its outer casing is rectangular, and the fastening method is a plug-and-pull type, which does not need to be rotated. The SC connector is directly plugged and unplugged, which is very convenient to use, but the disadvantage is that it is easy to fall out.


  ST type fiber patch cord 

   When an ST head is inserted, a bayonet is fixed on the half circle of rotation, with the disadvantage that it is easy to break; It is commonly used for optical fiber distribution frame. The shell is round and the fastening method is screw.

   LC fiber patch cord 

   It’s a connector for connecting SFP modules, it is made with an easy-to-operate modular jack latch mechanism. (SFP optical module default LC connector)

   MT-RJ type fiber patch cord 

   A square fiber optic end with integrated transceiver, one dual-fiber transceiver isintegrated. MTRJ type fiber optic patch cord consists of two high-precision plastic molded connectors and fiber optic cables. The outer parts of the connector are precision plastic parts, including a push-pull plug-in clamping mechanism.


   Simplex VS Duplex? 

   The fiber optic patch cords produced by the patch cord factory are also divided into simplex and duplex, so what is simplex? What is duplex? Simplex is data transfer only supported in one direction. At both ends of  the communication, one end is the transmitter and the other end is the receiver, which is not reversible. A radio station, for example, usually only sends a signal to the audience and does not receive the audience's signal.


   Duplex is divided into half duplex and full duplex. Half-duplex means that data can be transmitted in both directions on the signal carrier, but not at the same time. During the communication process, the transmitter and the receiver at both ends of the communication system can switch the direction through the transceiver/transmit switch, so as to realize the transmission in a single direction. Full-duplex is capable of bidirectional data transmission in both directions of the signal carrier at the same time, receiving data while sending data, requiring both the sender and the receiver to have independent receiving and sending capabilities at the same time. 

Whether it is simplex or duplex fiber optic patch cords can have single-mode and multi-mode modes. Single-mode and multi-mode have different applications. Generally speaking, single-mode is more suitable for long-distance transmission, and multi-mode is suitable for short-distance transmission. The choice of which mode of fiber patch cord is still based on the actual application scenario.

   Patch Cord Testing Tests 

Finally, in order to ensure the quality of optical fiber patch cord, five types of testing tests are generally carried out before handing over to customers.

   1. Insertion loss/return loss detection 

Insertion loss and return loss are key parameters that affect the performance of fiber patch cords. The TIA standard clearly specifies that the maximum insertion loss of the fiber patch cord is 0.75dB (that is, the acceptable maximum value). For most fiber patch cables on the market, the normal range of insertion loss is between 0.3dB and 0.5dB, and for some quality patch cord the range of insertion loss is between 0.15dB and 0.2dB. Return loss values are expressed in dB and are usually negative, so the bigger the number the better. The typical specifications range from -15 to -60 dB. According to industry standards, the return loss of Ultra PC polished fiber optic connectors should be greater than 50dB, and the return loss of bevel polish is usually greater than 60dB.PC type should be greater than 40dB. For multi-mode fiber, typical RL values are between 20 and 40 dB. 


   2. End face detection 

The cleaning of the end face of the optical fiber connector directly affects its performance. For example, scratches, pits, cracks, dust pollution, etc. on the end face of the optical fiber will lead to the loss of the connection signal, resulting in poor insertion and return loss.

   3. 3D interferometer detection 

3D interferometer testing is mainly to test the geometry of the fiber end face, and the parameters include curvature radius, vertex offset, fiber height, etc. The end face of the optical fiber patch cord needs 

to be ground into a spherical surface, but in actual production process it cannot be perfect.

   4. Optical fiber mechanical performance test 

Pull test, test the fiber patch cord under the specified pull force to verify the attenuation of the fiber and the safety factor of the fiber elongation strain.

   5. Ambient temperature experiment 

It is necessary to test the performance indicators of optical fiber connectors under different ambient temperature conditions. If you need more information or assistance with fiber optic products, please feel free to contact us at sales@o-pf.com and we will try our best to assist you.


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