What is an optical patch cord ? Components, types and how to choose
Contents
An optical patch cord — also called an optical connection cable, fiber patch cable or optical cord — is a short cable pre-terminated with connectors at both ends. It connects fiber optic devices to each other : switch ↔ optical drawer, PTO ↔ Internet box, SFP module ↔ patch panel.
Choosing the right patch cord involves four decisions : connector type, fiber type (single-mode or multimode), simplex or duplex, and jacket type. This guide explains each criterion with concrete examples.
What is an optical patch cord ?
In a fiber network, the devices (switches, SFP modules, OLT, ONT, PTO) communicate via cables. The optical patch cord is the short cable (typically 0.5 m to 30 m) that provides the final connection between two devices or between a device and a patching panel.
It differs from :
- Distribution cables — long multi-strand cables pulled through cable trays (100-500 m)
- Submarine cables — transoceanic, armored, several hundred fibers
- Pigtails — only one connectorized end, the other bare for splicing
The patch cord is the link that turns a "raw" fiber infrastructure into a usable network. Without patch cords, it is impossible to connect active equipment to patching panels.
The 4 components of a patch cord
| Component | Role | Common materials |
|---|---|---|
| Optical fibers | Carry the light signal (Tx + Rx in duplex) | Doped silica (9 µm single-mode or 50 µm multimode core) |
| Connectors | Attached at the ends, enable the connection | Zirconia ceramic (ferrule), plastic (housing) |
| Outer jacket | Mechanical and moisture protection | PVC, LSZH, polyurethane, steel (armored) |
| Aramid reinforcement | Tensile strength (Kevlar) | High-strength aramid fibers |
Elfcam patch cords all use zirconia ceramic ferrules (loss < 0.2 dB, lifespan > 500 cycles) and aramid Kevlar reinforcement to withstand tension. The internal fiber is G.657.B3 (bend-insensitive) for single-mode versions.
Connector types: SC, LC, FC, ST
The connector defines the mechanical compatibility with the equipment. Four standards dominate :
| Connector | Ferrule diameter | APC color | Typical application |
|---|---|---|---|
| SC | 2.5 mm | Green | FTTH PTO, operators, consumer equipment |
| LC | 1.25 mm | Green | Datacenter, switches, SFP/SFP+/SFP28 modules |
| FC | 2.5 mm | N/A (industrial) | Measurement, instruments, military |
| ST | 2.5 mm | N/A | Legacy installations, multimode |
| MPO/MTP | Rectangle 8-12 fibers | Green | High-density datacenter 40G/100G/400G |
Beware of APC vs UPC polarity
An APC connector (green, 8° angle) must NEVER be connected to a UPC adapter (blue, 0° angle). The connection is physically possible but causes catastrophic losses (>60 dB) and can damage the ferrules. Always check the color at both ends.
Elfcam patch cords by connector
- Ref 319 — SC/APC single-mode OS2 patch cord, compatible with French operators (Orange, SFR, Bouygues, Free)
- Ref 425 — LC/UPC ↔ LC/UPC OS2 duplex patch cord for datacenter
- Ref 400 — LC/UPC OM3 multimode duplex patch cord (aqua)
- Ref 1410 — LC/UPC OM4 multimode duplex patch cord
Simplex or duplex : 1 or 2 strands ?
The simplex / duplex distinction concerns the number of fibers in the patch cord :
- Simplex — a single fiber. Use : residential FTTH (the box sends and receives on the same fiber using two different wavelengths — PON principle).
- Duplex — two parallel fibers. Use : datacenter, switches, SFP modules. One Tx fiber (transmit), one Rx fiber (receive).
See our guide simplex or duplex fiber cable for the details on choosing.
Single-mode or multimode : which fiber in the patch cord ?
| Criterion | Single-mode OS2 | Multimode OM3/OM4 |
|---|---|---|
| Core diameter | 9 µm | 50 µm |
| Wavelength | 1310 / 1550 nm | 850 / 1300 nm |
| Jacket color | Yellow (or white) | Aqua (or violet OM4) |
| 10G reach | 10-80 km | 300-400 m |
| Relative cost | Medium | Lower (VCSEL transmitter) |
| Typical use | FTTH, operators, backbone | Short-distance datacenter |
In France, 99% of residential FTTH installations use single-mode SC/APC. In datacenters, multimode LC/UPC OM4 is the majority for intra-rack links.
Jacket types: PVC, LSZH, armored
| Jacket type | Use | Fire behavior | Price |
|---|---|---|---|
| PVC | Common indoor use | Flammable, emits toxic fumes | € |
| LSZH | Public buildings, datacenter | Flame-retardant, low smoke, halogen-free | €€ |
| Steel armored | Outdoor, rodent areas | Non-flammable (steel jacket) | €€€ |
| Polyurethane (PU) | Industrial, military | Flame-retardant, UV-resistant | €€€ |
For public-access buildings (ERP), French regulations require LSZH cables (Low Smoke Zero Halogen) that do not release toxic gases in case of fire. Our Elfcam indoor patch cords are all LSZH by default.
How to choose the length ?
Patch cords come in standard lengths : 0.5 / 1 / 2 / 3 / 5 / 10 / 15 / 20 / 30 m. Practical rule :
- Internal network rack — 0.5 to 3 m is enough
- Link between adjacent racks — 5 to 10 m
- PTO → box (residential) — 5, 10 or 20 m depending on configuration
- Short inter-building links — 30 m, beyond that switch to a distribution cable
Pro tip
Allow 10-15% slack on the length to manage bend radii and cable coiling in cabinets. A cable that is too taut accelerates connector breakage over the course of interventions.
FAQ — Optical patch cords
1Which patch cord to connect my PTO to my Internet box ?
2Difference between a patch cord and a pigtail ?
- Patch cord : connectorized at BOTH ends. Usable as is.
- Pigtail : connectorized on ONE side only. The other end is bare, intended to be fusion-spliced with a network fiber (distribution cable, optical drawer).
3Can an SC patch cord be connected to an LC connector ?
- Use a hybrid SC/LC patch cord (SC connector on one side, LC on the other) — Ref 405, 417
- Use a hybrid SC/LC adapter (coupler) between two standard patch cords
4Can an optical patch cord be extended ?
5Lifespan of an optical patch cord ?
6How to clean a patch cord connector ?
- Cleaning pen (one-click cleaner) — 500 uses for the ferrule
- Lint-free wipe + 99% isopropyl alcohol for the external part
- Fiber microscope to check cleanliness (x200 or x400)
7Patch cord OS2 or OS1 ?
8Patch cord delivery in France ?
In summary
An optical patch cord is chosen according to 4 criteria : connector (SC/APC residential, LC/UPC datacenter), fiber type (single-mode OS2 or multimode OM3/OM4), simplex or duplex, and jacket (LSZH for public buildings, armored for outdoor).
Browse our ranges of simplex patch cords and duplex patch cords to find the model suited to your installation.
