FTTH solutions for connecting SDUs

FTTH (Fibre to The Home) telecommunication networks provide very high-speed internet access via the optical fibre. However, connecting SDUs (Single Dwelling Units) to FTTH networks is quite different from connecting multi dwelling units and therefore requires other optical cables. So what are the FTTH solutions for the subscriber connection in SDUs?

What equipment is needed when deploying a FTTH network to a single dwelling ?

Although an optical fiber network starts from an Optical Connection Node and passes through different points before reaching the subscriber, the wording “subscriber connection” usually only refers to the last few miles of the optical network. This section of the network is also called the shared optical local loop or last mile access and connects the Optical Distribution Point (ODP) to the Optical Telecommunication Outlet (OTO) located inside the dwelling.

Last mile access: from the shared access point/street cabinet to the OTO

Fibre optic rollout to the premises is performed according to different stages and requires the use of various fibre optic boxes. The FTTH rollout starts at the Street Cabinet’s level (also called shared access point). This Fiber Distribution Point is a concentration point between the fiber optical loops of different operators and the optical network (common to all operators), used to connect all the identified premises. This is where the network is shared so all operators can deploy their networks. The Fiber Distribution Point can be located in different places depending on the deployment area:

  • The term Street Cabinet is employed when the fiber distribution hub is located in the street. This is usually the case for detached houses for example.
  • The term Shared Access Point is used in low density areas as it will enable to connect one or several neighborhoods.


The fibre optic rollout then requires the installation of an ODP, the optical closure in which the optical sockets or cables will be linked to enable access to the ultrafast fibre network.

The FTTH cabling system from the ODP to the OTO for SDUs

When connecting single dwelling units, a horizontal cabling rollout is the only type of cabling system installed to enable subscribers to have access to very high-speed networks. Horizontal rollout is specific for fibre optic deployments performed in the street. The ODP is therefore located outside the premise, usually at a few meters from the dwelling. The Optical Distribution Point can be pole or wall-mounted.

From the ODP installed on a pole or on a façade, the telecom field engineers roll out an aerial drop cable, like LX030PU (wear, tear and UV resistant), to an outdoor/indoor transition point where this outdoor FTTH cable will be connected to an indoor drop cable like LM1L (with a LSZH-FR outer sheath, fully compliant with CPR standards). These transition points located on the facade of a dwelling are available in various colours so they can blend in with the background as much as possible.

For indoor/outdoor double sheathed drop cables, such as LM4 or LM3, this transition is not necessary and the network can be deployed uninterruptedly as just one optical cable can be used for outdoor and indoor installations. Indeed, these dual sheath optical cables present two ripcords enabling to strip off the HDPE outer sheath in a couple of seconds, enabling field engineers to access a Low Smoke Zero Halogen Flame Retardant LM1L drop used for indoor applications. Thus, there is no need to perform a splicing.

FTTH end connection for SDUs

To complete the access to the very high-speed broadband networks, the next step is to enable the end connection and bring the optical signal up to the subscriber’s premises. This will be completed by the operator with which the end-user has decided to subscribe an offer. Thus, the operator is responsible to carry out the operation consisting into installing a drop cable between the ODP and the subscriber’s optical outlet. The Optical Terminal Outlet is the point of arrival of the optical fiber for all types of housing, old or new, and must comply with ARCEP recommendations by enabling the cabling of 1FO (OTO single-fibre), 2 or 4FO (OTO multi-fibre), depending on the area in which the connection is made.

New homes must be equipped with a DTIO: Optical Telecommunication Outlet. A DTIO is an OTO integrated to a data closure grouping together all the household’s low current inputs, i.e., the transportation of information. This intermediate optical distribution point consists of a box enabling the fiber to be stored and an optical connector to which the ONT (Optical Network Termination) will be connected. It constitutes the termination point of the optical cabling and therefore the limit of responsibility between the operator and the end customer regarding the maintenance of the network and the equipment. This optical pre-installation avoids the need to roll out optical cables from the shared access point or street cabinet to the customer's premises if they wish to be connected to the optical fibre network or to switch operator.

An Optical Telecommunication Outlet is installed inside the subscriber's house to connect the SDU to the optical fiber network