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What are the steps for fiber optic cable cutting

2022-08-15
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The definition of optical cable is believed to be clear to everyone without me saying more, so do you know optical cable cutover? So, what is optical cable cutover? What are the steps for fiber optic cable cutover? Let's go and find out together.

 

What is fiber optic cable cutover

Cutover: Literally, cut first and then connect. Optical fiber cutover mainly refers to the cutover of optical fiber trunk lines (upgrade and replacement of equipment, etc.). I am a wireless communication agent, and I have done several cutovers.

 

The cutover is generally an engineering project of the communication and maintenance company. For example, when the base station is reconstructed, it is necessary to carry out the cutover. It is usually carried out after 12 o'clock in the evening. If there are four people in a team, it can usually be done in three hours.

 

The definition of the detailed point is: the operation of the line and equipment in use will directly affect the services carried on it. The most critical step in the network transformation is the network cutover. Network cutover, also known as network migration, refers to physical or logical changes to the operating network. The most critical step in network transformation is network cutover.

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What are the steps for fiber optic cable cutting

1. Preparation for cutover

Resource survey: Extract the resources of the optical cable to be cut through the resource management system for on-site verification, as part of reporting the cutover plan.

 

Cutover report approval: According to cutover reporting requirements, cutover report is made

 

Resource review: After the cutover is approved, the on-site inspection of the resource usage of the cable segment to be cutover is carried out again, and the cutover site is thoroughly checked.

 

Equipment preparation: including instruments for cutover, vehicles, generators, tents, etc.

 

Preparation for machine line contact: machine line contact, confirm cutover report, contact person and contact number

 

On-site preparation: pre-layout of optical cables for cutover, ventilation of manholes, on-site pretreatment, etc.

 

2. On-site implementation of cutover

 

3. Management after cutover

 

4. Cutover scheme

4.1 Fiber reverse solution

The fiber-reversing solution is the first choice for fiber optic cable cutover without interrupting business. It is suitable for fiber optic cable line cutover with backup fiber optic cable routing. This solution mainly emphasizes the coordination and cooperation of maintenance and line departments. All services in the connected optical cable are transferred to the standby optical cable routing, and the vacant optical cable is cut over by the line personnel.

 

4.2 Tuning circuit scheme

The circuit adjustment method is to adjust the affected circuit in the process of optical cable cutover to the circuit in other optical cables, and then cut and connect after the optical cable is vacated.

 

The circuit adjustment mode is also an auxiliary means of the fiber rewinding method. When the spare fiber resources are not many, the large-capacity and important circuits are reversed, and the circuits are called out for other circuits.

 

4.3 Longitudinal section scheme

Longitudinal section method is a cutover method in which there is no spare optical cable routing, and the circuit can not be called out at the same time. The longitudinal section method is for the repair of the individual blocked fiber cores of the optical cable line, and does not affect other optical fibers with good performance in use.

 

Steps for cutting and connecting pipes in longitudinal section bundle-by-bundle:

●The personnel in the computer room call out the system in the bundle to be cut according to the circuit scheduling plan;

●On-site personnel longitudinally split and strip the optical cable to be cut;

●Separate the bundle tube longitudinally, check with the personnel in the computer room on site, and cut off the bundle tube for connection after confirming that the bundle tube to be cut and connected;

●The personnel in the computer room monitor synchronously to confirm that the optical fiber transmission characteristics are qualified and the fiber sequence is correct, and then return to the original system according to the circuit scheduling plan. After returning to normal, notify the cutover site that the fiber optic fiber cutover of the bundle tube is completed, and prepare for the next work;

●According to the above method, both sides of the machine line will cut other bundles one by one.

 

The steps of longitudinal section and pair-by-pair cutover:

●The personnel in the computer room call out the in-core system to be cut one by one according to the circuit scheduling plan;

●On-site personnel longitudinally split and strip the optical cable to be cut;

●Slit the bundle tube longitudinally, check with the personnel in the machine room on site, confirm the fiber core pair to be cut and then cut the fiber core pair for splicing;

●The personnel in the computer room monitor synchronously to confirm that the optical fiber transmission characteristics are qualified and the fiber sequence is correct, and then return to the original system according to the circuit scheduling plan. After returning to normal, notify the cutover site that the fiber core pair is cutover and ready for the next step;

●According to the above method, both sides of the machine line will cut other fiber core pairs one by one.

 

Use of longitudinal section scheme:

●Vertical split connection is aimed at the repair of the non-total resistance fault of the optical cable, and the total resistance fault should not be used.

●Longitudinal splicing is suitable for repairing non-total resistance faults of long-distance trunk optical cables. The local network optical cable is not recommended due to many faults and fewer cores.

●Special care should be taken to avoid damage to the intact bundled fiber.

●The length of the intervening optical fiber or optical cable should be 50-100 meters.

 

5. Problems that should be paid attention to in optical cable cutover

5.1 Formulation of cutover plan

Submit the cutover application report in advance according to the cutover reporting time limit, and in the cutover plan, specify the section name, trunk disconnection, cutover reason, location, time, cooperating personnel, division of labor for cutover personnel, vehicles, instruments and equipment, and the cutover plan. The following items should be paid attention to during the cutover:

 

1) Selection of cutover points

The cutover point should be selected as far as possible from the original joint position, taking into account factors such as transmission indicators and whether the operation is convenient, so as to reduce the joint loss caused by the cutover as much as possible. If the cutover point is far away from the original cutover point and the transmission index allows, you can place the cutover point in a suitable position in the routing.

 

2) Division of labor for cutover personnel, vehicles, instruments and equipment

● Arrange the personnel list, contact information, vehicles and instruments of the connection group and test group in a reasonable arrangement, and fully consider personal factors and on-site factors. In the case of insufficient local manpower, the superior department should be contacted as soon as possible to request reinforcements on personnel, vehicles, instruments and equipment. It is required to have a backup instrument at the cutover site and the test site, so that it can be dispatched in time when a certain instrument fails during the cutover process.

 

●Implement the specific responsibilities of the cutover commander, the responsible personnel and cooperating personnel of the continuity group and the test group, and clarify the specific contact method. Generally, at least two or more communication methods should be considered to ensure smooth communication between the cutover points and between the cutover points and the test points during the entire cutover process.

 

3) Cutover scheduling scheme

Be fully aware of system openness, spare cores, and core chromatograms for new/old cables. It is necessary to work out the sequence and steps of detailed scheduling, proofreading, identification, and connection of each fiber core and each system, and strive to restore the circuit in the shortest time.

 

When there is a spare bundle tube in the optical cable, the spare bundle tube should be used for scheduling, or the open systems in several bundle tubes can be scheduled together, and one bundle tube can be vacated for scheduling. When the spare bundle tube cannot be guaranteed, as long as there are two spare fibers with good performance in the optical cable, it can meet the needs of fiber core scheduling with service cutover. The priority order of circuit scheduling is used to schedule important service circuits.

 

4) Emergency dispatch plan

Due to the use of service cutover, there are certain risks. In order to avoid accidents in the process of optical cable stripping and splicing, resulting in circuit interruption, or business interruption due to other reasons, a detailed circuit scheduling emergency plan should be formulated before the cutover. If the optical fiber is interrupted due to misoperation, the disconnected fiber should be reconnected as soon as possible, or the circuit should be adjusted to quickly restore the system. Therefore, it is essential to formulate detailed troubleshooting methods and emergency contact methods in the emergency dispatch plan.

 

5.2 Preparations before cutover

After the cutover application report is approved, the preparatory work before cutover becomes particularly important. We should fully do all the preparatory work before the cutover, which is mainly reflected in the following aspects.

 

1) Collect and organize the original data of the line.

 

2) Familiar with the performance of the transmission equipment in use, and record the performance parameters of the cutover section, such as optical power and return loss value.

 

3) Check whether the laying of the new optical cable is safe and reasonable, and test and confirm the parameters of the optical cable.

 

4) Check the cutover equipment and tools and communication tools to ensure that various instruments and tools are in normal use.

 

5) Check the cutover scheduling plan on site, check whether the cutover site has changed, and whether the equipment in the equipment room and the pigtail have changed.

 

6) The cutover team arrives at the cutover site 2 hours before the cutover to make preparations, excavate the operation pit and the joint pit, check the optical cable lines to be cutover, and take on-site protection and various safety measures as well as Stripping of new optical cables. For direct buried optical cables, routing detectors are used to detect specific locations and buried depths. For overhead optical cables, check the cable reservation. Check and arrange the connection tools, and check whether the communication method is smooth.

 

7) Each test team arrives at the site 1 hour in advance to confirm the position of the ODF rack, mark the pigtails, and at the same time conduct a retest, check and register for the prepared and scheduled fibers. Check the power supply and lighting conditions of the equipment room, contact the network management center and the cutover point, confirm that the contact tools are in good condition, and make all preparations.

 

8) 4 hours before the cutover, call all cutover personnel to hold a special meeting with business cutover, to further report the operation steps of the cutover plan, and to implement the availability of cutover personnel, vehicles, instruments and equipment and the precautions to be noted during the cutover. matter.

 

5.3 Formal cutover

When the cutover approval time is reached, the cutover will officially start, and the cutover and test personnel should operate according to the cutover plan previously formulated. During the operation, the following matters should be noted:

 

1) The tester must test the spare fiber with a light source and an optical power meter to ensure that the transmission characteristics of each fiber are good, and to determine whether the fiber has a mandarin duck fiber.

 

2) The tester must clean the pigtail head and flange before plugging and unplugging the optical fiber.

 

3) The tester should notify the cutover site personnel to do a microbend test before the fiber is broken to judge the correctness of the fiber core, especially when there is a mandarin duck fiber, and carefully check the accuracy of each fiber. In addition, when the tester finds that the splicing quality is unqualified during the testing process, the splicing personnel should be notified to re-weld in time.

 

4) The connection personnel must connect the chromatogram and fiber core according to the cutover plan, and strictly prevent the phenomenon of wrong fiber and wrong pipe. Care should be taken during the splicing process to avoid injury to the fiber in use. Once the fiber in use is injured, the fusion splicing should be restored as soon as possible, or the circuit should be adjusted as soon as possible.

 

5) Testers should synchronously perform fiber-by-fiber and system-by-system scheduling. If the system cannot recover quickly after adjusting the fiber, you need to restore the fiber to the original position, and then determine the cause of the failure, which can be confirmed by the rack light, the CD-ROM alarm light and the network management center, and finally the network management center confirms.

 

6) The tester should record in detail the attenuation value of each fiber before and after the cutover, as well as the attenuation value of each connector position, including the two test values ​​of the light source, optical power meter and OTDR. Fiber length should also be recorded in detail.

 

7) The second fiber adjustment should be done after all the empty fibers at all cut points have been connected, and confirmed that the connection performance is good, there is no wrong fiber, wrong pipe phenomenon, and the connection point has placed the connected empty fiber reel in the reel box. carried out later.

 

8) The tester should record the recovery time of each interruption in detail.

 

5.4 Implementation of box sealing

When all the fibers have been connected and coiled in the fiber reel box, the rack warning light and the CD warning light disappear, and the box can be sealed after being confirmed by the network management center. The following issues should also be paid attention to during the sealing work:

 

1) The direct buried optical cable joint box should be installed with monitoring tail cable, sealed the joint box, buried in the joint hole dug in advance, and reserved the optical cable reel for burying. After the overhead optical cable joint box is installed, it should be fixed on the pole, and the installation of the reserved basket and the coiling of the optical cable should be done well.

 

2) During the installation of the splice box, the tester should do a good job of monitoring and analyze whether the optical fiber has attenuation changes during the installation of the splice box.

 

3) When the fiber core is spliced ​​and safely placed in the fiber plate, the personnel at each cutover point should notify the test personnel in the equipment room to conduct the test before sealing the box. After the splice box is sealed, the computer room tester should perform the test again. When the splice box is buried in the splice pit or fixed on the pole, the tester in the equipment room should also continuously test and observe the change of the optical fiber attenuation parameters at all times.

 

4) After all cutover operations are completed, contact the network management center to confirm that there is no abnormality, then check the tools and instruments and evacuate the site.

 

5.5 Follow-up work

After the cutover is completed, report the cutover completion data in time according to the time limit, and prepare the data that needs to be revised and improved due to the business cutover, such as the change table of optical cable line equipment, the comparison table of marker stone/pole length and fiber length, and the optical cable routing diagram. , maintenance diagrams, circuit diagrams, etc.

 

6. Mistakes that are prone to occur in optical cable cutover

1) When there are multiple new fiber optic cables of the same specification and type in the same cutover site, if the two ends of each fiber optic cable are not marked with the same color and are in the same pipe hole, it is easy to make mistakes during cutover.

 

2) The old optical cable to be cut is usually marked with red tape to mark the reserved end, but after the old optical cable is pulled out of the manhole, is it the left end or the right end of the red tape when cutting? It is very easy to make mistakes. In fact, blue tape should be used to mark the discarded end. When cutting, cut off between the red tape and the blue tape and keep the red end so that there will be no mistake.

 

3) In the same old optical cable to be cut, because there are multiple splice boxes and various types of optical cables, and the splice boxes are not opened before the cut and the fiber is recorded and recorded, the wrong fiber is inevitable during cutover. .

 

4) In the optical cable cutover of the incoming line, since the optical cables in different directions all go through the same pipe, it is easy to get the wrong direction during the cutover.

 

5) In the safety management of on-site cutover, a little carelessness will lead to safety accidents. If you enter the manhole without proper ventilation, use an open flame in the manhole, no warning signs around the manhole, no warning signs when pumping water, refuel the oil machine while smoking, work on the pole without checking with a test pen , start the cable opening without the review and approval of the person in charge of the cutover point, etc.

 

The cutover can only be done at night. When the temperature is close to 0 degrees outdoors, the face, hands, and ears are all frozen red, but the work in hand cannot be stopped for a moment. It takes several hours from preparation to completion.

 

Every cutover is like going to a battlefield, the atmosphere is tense and orderly.

 

The above is the entire content of what is optical cable cutover and what steps are involved in optical cable cutover. In fact, optical fiber cutover simply refers to an access construction technology that connects new, reconstructed and expanded optical cable transmission lines to existing optical transmission networks.

 

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