The line professional outsourced maintenance training manual mainly includes eight parts: basic knowledge, maintenance items, maintenance cycles and standards, maintenance evaluation indicators, maintenance management systems and processes, maintenance operation standards and steps, instrument and equipment usage, emergency response plan principles, and typical fault cases. It also contains some product introductions and questions.
**Part One: Basic Knowledge**
1. **Fiber Optic Classification**
According to the number of transmission modes, fiber optics can be divided into multimode fibers and single-mode fibers:
Single-mode fibers are further classified by ITU (International Electrotechnical Commission) standards into four types: G.652, G.653, G.654, and G.655.
(1) **G.652 Fiber**: Also known as standard single-mode fiber (SMF), it refers to a fiber with a zero-dispersion point (where dispersion is zero) near 1310nm.
(2) **G.653 Fiber**: Also called dispersion-shifted fiber (DSF), it refers to a fiber with a zero-dispersion point around 1550nm. Compared to G.652 fibers, the zero-dispersion point has shifted, hence the name dispersion-shifted fiber.
(3) **G.654 Fiber**: This is a cutoff wavelength-shifted single-mode fiber. Its design focuses on reducing attenuation at 1550nm, with the zero-dispersion point still near 1310nm. Therefore, the dispersion in the 1550nm window is relatively high. G.654 fibers are mainly used for submarine optical communications.
(4) **G.655 Fiber**: Since the zero-dispersion point of G.653 fibers is near 1550nm, DWDM systems working at this zero-dispersion wavelength are prone to four-wave mixing effects. To avoid this effect, the zero-dispersion point is shifted away from the 1550nm range used by DWDM systems. This type of fiber is called non-zero dispersion-shifted fiber (NDSF).
2. **Optical Cable Classification**
Below is a detailed introduction to optical cables classified by cable core structure. Optical cables are categorized into four major types based on their core structures: stranded-type optical cables, skeleton-type optical cables, bundle-tube optical cables (central tube type), and ribbon-type optical cables, as shown in Figure 1.4.
- **Stranded-Type Optical Cable**: Tight-buffered or loose-tube fibers are helically stranded around a central strengthening element. Compared to central-tube optical cables, stranded-type cables have more complex production equipment but offer a higher fiber count (up to 144 cores) and easier control over excess fiber length.
- **Skeleton-Type Optical Cable**: Primary or secondary coated tight-buffered fibers are placed lightly in skeleton slots. The production process for skeleton-type cables is relatively complex due to an additional production line for the skeleton. Skeleton-type cables typically have up to 12 cores.
- **Central (Bundle) Tube Optical Cable**: Loose-tube fibers (single-core or multi-core) are placed directly in the center position without stranding. This arrangement minimizes bending-induced losses. Strengthening elements may either consist of two parallel high-carbon steel wires parallel to the central tube inside the outer jacket or multiple low-carbon steel wires spirally wound around the central tube.
- **Ribbon-Type Optical Cable**: 4-12 fiber cores are arranged in rows to form a ribbon unit, and multiple ribbon units are cabled together in a specific arrangement. This compact structure allows for the creation of high-density user cables with thousands of cores.
**Optical Cable Type Composition**
An optical cable type consists of five parts:
I. **Classification Code and Meaning**:
- GY: Outdoor communication optical cable
- GR: Flexible communication optical cable
- GJ: Indoor communication optical cable
- GS: Equipment internal communication optical cable
- GH: Submarine communication optical cable
- GT: Special communication optical cable
II. **Strengthening Element Code and Meaning**:
- No symbol: Metal strengthening element
- F: Non-metal strengthening element
- G: Heavy-duty metal strengthening element
- H: Heavy-duty non-metal strengthening element
III. **Derived Feature Code and Meaning**:
- D: Ribbon fiber structure
- G: Skeleton slot structure
- B: Flat structure
- Z: Self-supporting structure
- T: Filled structure
IV. **Sheath Code and Meaning**:
- Y: Polyethylene sheath
- V: Polyvinyl chloride sheath
- U: Polyurethane sheath
- A: Aluminum-polyethylene bonded sheath
- L: Aluminum sheath
- G: Steel sheath
- Q: Lead sheath
- S: Steel-aluminum-polyethylene composite sheath
V. **Outer Sheath Code and Meaning**:
The outer sheath refers to the armor layer and its external sheath. Refer to Table 2 for the codes and meanings.
**Optical Cable Color Spectrum**
The optical cable color spectrum is divided into red-green lead colors and full-color spectrum:
Red-Green Lead Color Spectrum: Starting with red-green tubes, the white tubes are arranged clockwise as white tube 1, white tube 2, etc.
Fiber Color Spectrum: Blue, orange, green, brown, gray, white, red, black, yellow, purple, pink, light green.
Blue 1, 12-core
**Three, Cables**
Common all-plastic cable model readings:
HYA: Copper core solid polyolefin insulated aluminum-plastic bonded comprehensive sheath indoor communication cable
HYFA: Copper core foamed polyolefin insulated aluminum-plastic bonded comprehensive sheath indoor communication cable
HYPA: Copper core foamed skin polyolefin insulated aluminum-plastic bonded comprehensive sheath indoor communication cable
HYAT: Copper core solid polyolefin insulated filled aluminum-plastic bonded comprehensive sheath indoor communication cable
HYFAT: Copper core foamed polyolefin insulated aluminum-plastic bonded comprehensive sheath indoor communication cable
HYPAT: Copper core foamed skin polyolefin insulated aluminum-plastic bonded comprehensive sheath indoor communication cable
HYPAT23: Copper core foam/solid skin polyethylene (polyolefin) insulated, petroleum jelly filled, painted aluminum tape bonded shielded polyethylene sheath, double-layer anti-corrosion steel tape wrapped armored outer sheath, urban telephone communication cable.
HYAC: Copper core solid polyethylene (polyolefin) insulated, painted aluminum tape bonded shielded polyethylene sheath, self-supporting urban telephone communication cable.
HYV: Copper core solid polyethylene insulated, polyvinyl chloride sheathed aluminum foil wrapped tape, urban telephone communication cable.
HJVVP: Copper core polyvinyl chloride insulated, polyvinyl chloride sheathed, aluminum foil tape wrapped, indoor communication cable.
**Significance of Common All-Plastic Cable Specifications Codes**
Typically, the specifications code for all-plastic cables is placed after the cable model and is represented by numbers.
For star-twisted cables, the sequence is:
Star-twisted group count × Number of conductors per group × Conductor diameter (mm)
50×4×0.5 = 100-pair cable
For pair-twisted cables, the sequence is:
Number of conductor pairs × Number of conductors per pair × Conductor diameter (mm)
100×2×0.5 = 100-pair cable
**Four, Pipes**
1. Double-wall corrugated plastic pipes, with pipe outer diameters generally ranging from 100~110mm (can be produced according to needs), single length of 6 meters, widely used in trunk and distribution pipelines within cities, bridge trunk pipeline construction, etc.
2. Silicon core plastic pipes, with inner walls having a silicon core layer that provides smoothness and low friction coefficient, commonly used as protective pipes for optical cables. Outer diameters range from 32~60mm, each pipe can reach up to 2000 meters in length.
3. Multi-hole pipes (single holes circular or hexagonal), produced in a multi-hole integral structure, evenly stressed, compact structure. Hole counts from 3~7, single pipe outer diameter generally ranges from 25~32mm, can also be produced in arbitrary combinations according to needs. Pipe lengths are usually above 6 meters, coiled ones can reach up to 200 meters in length, coil lengths can also be produced according to needs.
4. Honeycomb pipes (single holes pentagonal or circular), produced in a multi-hole integral structure, evenly stressed, compact structure. Hole counts from 3~7, single pipe outer diameter generally ranges from 25~32mm, can also be produced in arbitrary combinations according to needs. Pipe lengths are usually above 6 meters. Usage scope should meet the requirements of multi-hole pipes.
5. Grating pipes (single holes square), can be combined into different hole diameters and different hole counts of square or rectangular structures according to needs. Single pipe diameter can range from 28~90mm, can also be produced in arbitrary combinations according to needs. Pipe lengths are normally above 6 meters. Application scope same as multi-hole pipes.
6. For pipe selection, cement pipes should be prioritized for newly constructed roads in urban areas; plastic pipes should be chosen for sections with various integrated pipelines and complex terrains in existing urban roads; plastic pipes should be selected for dedicated optical cable construction pipelines, and the pipe holes and combinations should be selected according to needs.
**Five, Poles**
1. **Poles**
Poles should generally use Ф15cm tip diameter, 1/75 taper pre-stressed concrete poles, with a basic pole height of 8m. Pole specifications for special sections should follow the design in the construction drawings.
Pole burial depth requirements see Table 12.
**Table 12 Pole Burial Depth Requirements:**
| Pole Height | Applicable | Burial Depth (m) | General Soil | Hard Soil | Paddy Field/Wetland | Rock |
|-------------|-----------|------------------|--------------|------------|---------------------|-------|
| 7m×15cm | Rural lines | 1.3 | 1.2 | 1.4 | 1.0 | |
| 8m×15cm | Urban/suburban lines | 1.5 | 1.4 | 1.6 | 1.2 | |
| 9m×15cm | Road/River lines | 1.6 | 1.5 | 1.7 | 1.4 | |
| 10m×15cm | Road/River lines | 1.7 | 1.6 | 1.8 | 1.6 | |
| 12m×15cm | Road/River lines | 2.1 | 2.0 | 2.2 | 2.0 | |
2. **Guy Wires**
- Terminal rod guy wire: Should select one grade larger than the hanger wire (7/2.6).
- Corner rod guy wire: When corner depth ≤13m, the guy wire is the same as the hanger wire; when corner depth >13m, select one grade larger than the hanger wire.
- Intermediate rod guy wire: When the loads on both sides of the intermediate rod are different, a top-head guy wire should be set, and the top-head guy wire specification should match the larger side's hanger wire.
- Anti-wind rod side guy wire, anti-ice rod side guy wire, and inline guy wire all select the same specification as the hanger wire.
- False termination, force-relieving knot, long-span rod, and high guy pile rod with corner depth >3m, the guy wire specification matches the hanger wire specification.
- Support rod requirements: Consider the bending resistance at the support point. When corner depth >5m, the pole strength should be one level stronger than general poles, and corner depth should be <10m. The ratio of distance to height is generally 0.6, and the support rod tip diameter should not be less than 4/5 of the connected pole diameter.
**Overhead Hangers**
Overhead optical cables are preferably hung using an additional hanger method, with each hanger generally carrying only one optical cable. Depending on engineering requirements, self-supporting methods can also be adopted. Optical cables can be installed on hangers using cable hooks or spiral binding.
**Selection of Hanger Specifications**
The overhead optical cable lines in Jiangsu Province belong to light and medium load zones, with standard pole distances generally being 50m.
- Galvanized steel strand 7/2.2: Used for optical cables.
- Galvanized steel strand 7/2.2: Used for cables below 200 pairs.
- Galvanized steel strand 7/2.6: Used for cables between 200-400 pairs.
- Galvanized steel strand 7/3.0: Used for cables between 400-800 pairs.
**Hooks**
Hook specifications: Preferably use 25mm plastic-supported hooks or 25mm nylon-supported board hooks, and avoid using metal-supported board hooks.
- 25mm: Used for cables below 50 pairs (0.4mm diameter)
- 35mm: Used for 100 pairs (0.4mm diameter)
- 45mm: Used for 200 pairs (0.4mm diameter)
- 55mm: Used for over 300 pairs (0.4mm diameter)
- 65mm: Used for over 400 pairs (0.4mm diameter)
**Hook Spacing:** 50±3cm