Connection cable for fibre-optic routers

Fibre-optic connection cables for routers – OS2 with LC/APC & SC/APC

DINIC fibre optic connection cables for FTTH, FTTB and direct fibre-optic routers: pre-terminated OS2 single-mode cables with precision APC connectors for connecting fibre-optic sockets or GF-TA units to compatible routers, fibre modules or optical terminal equipment.

Choices include LC/APC to LC/APC and LC/APC to SC/APC in various lengths up to 50 m. Matching APC adaptors and couplers complete the range.

OS2 9/125 µm single-mode
Simplex 1 fibre optic
APC 8° for low back reflection
up to 50 m flexible router positioning

Which connector combination do you require?

LC/APC → LC/APC: The router/fibre module and fibre optic socket are fitted with LC/APC connectors. LC/APC → SC/APC Router side: LC/APC; fibre optic socket or GF-TA: SC/APC. APC adaptors & couplers For extension, adaptation and existing FTTH installations.
Do you have a separate ONT? In that case, the optical connection usually terminates at the ONT. An Ethernet network cable is then typically used to connect the ONT to the router’s WAN port. A direct fibre-optic cable to the router is only required if the router itself uses a suitable fibre-optic connection or a fibre module.
Which cable for which router? LC/APC, SC/APC, GF-TA, ONT and FRITZ!Box Fibre explained. LC or SC? Connector types, APC, UPC and Simplex explained clearly. Why OS2? Comparing single-mode and multi-mode, as well as OM3, OM4 and OS2.

Choosing the right fibre-optic cable for routers and FTTH

For a fibre-optic connection, the fibre type, connector design, end-face polish and termination technique must all be compatible. OS2 single-mode fibre is typically used for FTTH and FTTB connections. The DINIC patch cables in this category use OS2 9/125 µm, simplex and APC connectors with an 8° cut.

The most important question is therefore not just ‘Which router do I have?’, but: Which socket is on the router or fibre module, and which socket is on the GF-TA or the fibre-optic terminal box?

Direct fibre-optic router or separate ONT?

Router connected directly to fibre

If the router has an integrated fibre-optic modem or a suitable fibre/SFP module, it is connected directly to the GF-TA or fibre-optic socket via a suitable OS2 connection cable.

Separate ONT

With an Optical Network Terminal (ONT), the fibre-optic cable terminates at the ONT. The connection from the ONT to a standard router is then usually made via Ethernet to the WAN port.

GF-TA / fibre-optic socket

Depending on the network operator, the subscriber termination may feature, for example, an LC/APC or SC/APC connector. This connection determines the required connector type on the socket side.

Important clarification regarding selection: A separate ONT is not normally connected to the WAN port of a standard router via an additional fibre-optic cable. The fibre-optic signal terminates at the ONT; Ethernet is then used.

LC/APC or SC/APC – which cable do I need?

Router / Fibre module GF-TA / Fibre-optic socket Suitable connection cable
LC/APC LC/APC OS2 Simplex LC/APC 8° → LC/APC 8°
LC/APC SC/APC OS2 Simplex LC/APC 8° → SC/APC 8°
Ethernet WAN Fibre optic cable terminates at the ONT ONT → Router, usually via a LAN/Ethernet cable
different connector different connector Check technical connections carefully before ordering
LC/APC → LC/APC OS2 Simplex for installations with LC/APC at both ends. LC/APC → SC/APC OS2 Simplex for LC/APC on the router side and SC/APC on the GF-TA or fibre-optic terminal. APC adaptors & couplers For extension, adaptation and existing optical connections.

What does OS2 9/125 µm mean?

OS2 is a single-mode fibre class. The specification 9/125 µm describes the approximate core diameter of 9 µm and the cladding diameter of 125 µm.

Single-mode fibre is used in FTTH and FTTB because the optical transmission is designed for long distances and the corresponding access networks.

Do not confuse this with OM3 or OM4: OM3 and OM4 are 50/125 µm multimode fibres intended for other network and data centre applications. An OM4 patch cable is not a substitute for an OS2 FTTH connection cable.

What does ‘simplex’ mean?

The router connection cables in this category use a single optical fibre – simplex. This distinguishes them from many traditional Ethernet fibre-optic patch cables in data centres, which are often designed as duplex cables with two fibres.

FTTH access networks can transmit and receive data using different wavelengths over the same single-mode fibre. Therefore, a single optical fibre is sufficient for typical FTTH router connections.

What does APC 8° mean?

APC stands for Angled Physical Contact. The fibre end face is polished at an angle – typically around 8°.

This design reduces disruptive back reflections and is therefore frequently used in single-mode, telecommunications and FTTH applications.

Do not connect APC and UPC directly to one another. The end faces have different geometries. Even if the external connector type is, for example, LC for both, LC/APC and LC/UPC are not the same optical connection.

LC and SC – what is the difference?

Feature LC SC
Ferrule 1.25 mm 2.5 mm
Design Compact larger and easy to grip
Locking mechanism Latching mechanism Push-pull
FTTH application Commonly found on fibre modules and certain routers Commonly found on GF-TA units, connection boxes and handover points
APC possible? Yes Yes

Which cable for the FRITZ!Box Fiber?

For the relevant fibre SFP modules on the FRITZ!Box 5530 Fiber and 5590 Fiber, the module side is marked LC/APC. The required counterpart depends on the fibre-optic socket installed.

  • GF-TA with LC/APC → LC/APC to LC/APC
  • GF-TA with SC/APC → LC/APC to SC/APC
The router model alone is not enough: the same router may require a different connection cable depending on the network operator and the existing connection socket. Therefore, always check both ends of the cable.

AON, GPON or XGS-PON – what does this have to do with the cable?

AON, GPON and XGS-PON describe the optical network or access technology used. LC, SC and APC, on the other hand, describe the mechanical connection or the fibre end face.

A cable may therefore fit perfectly mechanically, even though the router or fibre module is not technically compatible with the provider’s network.

Before buying a router: Don’t just check the fibre connector. The router or fibre module must also support the access technology used by the network operator.

What cable length should I choose?

DINIC connection cables are available in various lengths of up to 50 m, depending on the series. This allows the router to be positioned independently of the installation location immediately adjacent to the GF-TA.

When selecting the length, please note:

  • measure the actual cable route
  • Take door frames, skirting boards and cable ducts into account
  • allow for a reasonable amount of slack
  • do not create unnecessarily large cable loops
  • Do not kink the fibre-optic cable
  • Avoid tight bending radii
  • Do not transfer tensile stress via the plug

When do I need an adapter or a coupler?

Adapters and couplings are useful when an existing installation needs to be modified or extended.

Typical applications:

  • connecting two compatible APC connection cables
  • extending existing LC/APC connections
  • Mechanically adapting LC/APC and SC/APC to one another
  • Servicing and upgrading existing FTTH connections
Where possible, choose a directly compatible connector combination: a single, end-to-end LC/APC→SC/APC cable is often more straightforward than an LC/APC cable plus an additional adapter and a second cable. Each additional optical connection point also contributes to the attenuation budget.

Check these four points before ordering

1 Where does the fibre end?
Directly at the router or already at a separate ONT?
2 Check
the router side For example, LC/APC on the fibre module.
3 Check
the GF-TA LC/APC, SC/APC or another type?
4 Check
the network technology The router or module must also be technically compatible with AON, GPON, XGS-PON or the provider’s technology in use.
Which fibre-optic cable for which router? Detailed selection guide for FRITZ!Box Fiber, GF-TA, ONT, LC/APC and SC/APC. LC, SC or ST? Fibre-optic connectors, ferrule sizes, simplex, duplex, APC and UPC explained. OM3, OM4 or OS2? Compare single-mode and multi-mode fibres, as well as typical applications.

Frequently asked questions about fibre-optic connection cables for routers

Which fibre-optic cable do I need for my router?

First, check the connection on the router or fibre module, and then the connection on the GF-TA or the fibre optic socket. Typical combinations are LC/APC to LC/APC and LC/APC to SC/APC.

What is LC/APC to LC/APC?

Both ends of the OS2 single-mode cable have an LC connector with APC polishing. This type is suitable if both the router/fibre module and the fibre optic socket use LC/APC.

What is LC/APC to SC/APC?

The cable has a compact LC/APC connector on one end and a larger SC/APC connector on the other. This allows different types of FTTH connections to be connected directly.

Do I need a media converter between LC/APC and SC/APC?

No. Different connector types alone do not require a media converter. A pre-terminated LC/APC-to-SC/APC cable connects both mechanical connectors directly. The optical technology of the devices must, of course, be compatible.

Why is the cable simplex?

Typical FTTH connections operate via a single single-mode fibre. Transmission and reception can take place using different wavelengths over the same fibre.

Is OS2 suitable for fibre-optic routers?

Yes. FTTH and FTTB access networks typically use single-mode fibres. The DINIC router connection cables in this category are specified as OS2 9/125 µm.

Can I use OM4 instead of OS2?

No. OM4 is multimode 50/125 µm and is intended for other optical network applications. OS2 single-mode is used for typical FTTH router connections.

Do I need a fibre-optic cable from the ONT to the router?

Not normally, if you have a separate ONT. The fibre ends at the ONT. The connection from the ONT to the WAN port of a standard router is usually made via Ethernet.

Can I connect APC and UPC to each other?

APC and UPC should not be connected directly to one another because the fibre end faces have different geometries.

Can I position my router 20 or 50 metres away from the fibre-optic socket?

In principle, flexible router positioning is possible with a suitably long, technically compatible OS2 connection cable. The cable must be laid correctly and without kinks or excessively tight bends.

Select a DINIC fibre-optic patch cable suitable for the FTTH connection

OS2 Simplex with LC/APC or SC/APC, as well as suitable adaptors and couplers for direct fibre-to-router connections, GF-TA and professional FTTH/FTTB installations.

LC/APC → LC/APC LC/APC → SC/APC APC adaptors Router guide