Inside FTTH: Ok, So Now You Have Fibre Throughout the Building – What Happens in the Apartments?

 


I’m sure that we’re all aware by now that in this day and age, having access to high-speed internet is not considered a luxury. It is more of a realistic expectation —if not a necessity. 

Fibre to the Home (FTTH) or Fibre to the Premises (FTTP) technology enables this demand by providing ultra-fast broadband connections directly to residential units. But what exactly goes on behind the walls of a multi-dwelling unit (MDU) or apartment building to make FTTH possible?

We design fibre infrastructure systems for all types of building and campus environments to cater for many types of signal distribution, (VoIP, IPTV, CCTV, Door Entry systems, Building Management etc..) and there are a number of key components and infrastructure used in a standard FTTH (FTTP) installation in an apartment building, including elements such as the QDSA, STOA, fibre splice holder, and optical fibre socket. 

We go through these in more detail below:

The Journey of Fibre in an Apartment Building

1. QDSA (Building Optical Distribution Cabinet)

What it is:
The QDSA (often referred to as the building distribution point or BDCOM) is typically located at the base of the building—usually in a secure telecom room or basement.

What it does:

  • It serves as the demarcation point between the service provider’s external fibre network and the building’s internal distribution.
  • It receives incoming optical fibres from the outside plant (OSP) and redistributes them vertically or horizontally to various floors or units.
  • It houses splitters (in the case of a (Passive Optical Network) PON setup), patch panels, and splice trays.

Why it matters:
The QDSA is essentially the “brain” of the building’s fibre network. It determines how fibres are allocated to tenants and helps ensure signal quality is maintained throughout the system.

2. STOA (Optical Termination Box at Floor Level)

What it is:
The STOA (or splitter terminal optical assembly) is typically installed in a riser shaft or hallway cabinet on each floor. Think of it as a mini-distribution hub for that floor.

What it does:

  • It routes fibres from the QDSA to individual apartments.
  • It often includes a splice point or mini patch panel to organize and manage the fibres going to each flat.
  • In cases where multiple apartments are served from a single fibre, a small optical splitter might be housed here.

Why it matters:
The STOA provides a clean, manageable hand-off point for each floor, making troubleshooting and future upgrades easier.

3. Fibre Splice Holder

What it is:
A small yet critical component, the fibre splice holder is found inside the QDSA or STOA and is designed to neatly and safely store fusion splices.

What it does:

  • Protects fusion splices from mechanical stress and environmental damage.
  • Organizes multiple splices for easier maintenance and identification.
  • Maintains proper bend radius and fibre integrity.

Why it matters:
Good splice management ensures long-term network reliability. Poorly managed splices can cause signal degradation or complete service failures.

4. Optical Fibre Socket (OTO – Optical Termination Outlet)

What it is:
Installed inside each apartment, this is the end-point of the fibre cable—the subscriber interface.

What it does:

  • Terminates the fibre optic cable in the customer’s living space.
  • Connects to the Optical Network Terminal (ONT) or modem via a fibre patch cord.
  • Provides a clean, secure, and standards-compliant outlet for fibre internet service.

Why it matters:
A properly installed optical socket ensures optimal signal delivery to the customer and makes it easy to plug in or upgrade devices.

Typical Installation Flow

  1. External Fibre Entry: Service provider runs fibre to the QDSA.
  2. Distribution via QDSA: Fibres are patched or spliced and routed to floors.
  3. Floor-level Management via STOA: Fibres branch to individual units.
  4. Termination in Apartments: Fibre terminates at the optical socket inside each apartment.
  5. Customer Equipment: ONT or router connects to the optical socket, completing the connection.

The Final Piece of the Puzzle

Building a fibre infrastructure in an apartment isn’t just about pulling cable—it’s a carefully engineered system with components working together to ensure high-speed, reliable service for every resident. From the centralized QDSA to the optical fibre socket in your living room, each element plays a key role.

As FTTH becomes the new standard, understanding the infrastructure behind it helps property infrastructure designers, managers, tenants, and service providers align expectations and ensure successful installations.

Have questions about FTTH setups in your building? Drop them in the comments—we’d love to help explain further!

 


Comments

Post a Comment

Popular posts from this blog

What Do You Really Know About Multicast in Local Area Networks?

Image
  How are high-bandwidth applications like IPTV and video able to be sent over any LAN environment to many recipients safely and optimally without causing havoc with network bandwidth? Well, good design practices in networks for a start - and another is to use multicast. The vast majority of systems that transport any sort of AV traffic over the IP network today use multicast as their preferred method of transport. (I say the vast majority as some, believe it or not, use other less efficient methods, such as broadcast….) And they use multicast with good reason. It is the most efficient mechanism on the network available for transporting information (especially large-bandwidth data) from one source to many receivers. Unlike non-real time traffic such data which is transported as unicast, the network has to treat high-bandwidth, real-time traffic like video that needs to be received by a number of endpoints simultaneously, differently. It uses multicast to do this. In this ...
Read more

AVoIP, Industry Buzzwords and Market Hype – Cutting Through the Cr*p to Focus on What’s Important.

Image
  Don’t you just love industry buzzwords. AV over IP. Networked AV.   Networked Video. IPTV on the LAN. Even HDMI over Ethernet. All pretty much the same thing expressed in different ways. Every vendor tries to coin ‘their’ phrase – a slightly different take on a current technology trend or ‘buzz-term’ that’s riding high in the industry. It’s easy to be taken in by the hype, publicity and industry noise with this stuff, but whatever anyone wants to call it, distributing AV signals over an IT network is where things have been going for a long time, whether you like it or not. So sorting out the ‘FUD’ (fear, uncertainty, doubt) factor, or even worse that FOMO (fear of missing out) feeling, is crucial so you can then focus on what’s actually important in all this hyperbole. So maybe this will perhaps simplify things..   This is Nothing New Many of the challenges faced in today’s AV world – not only by AV integrators but also IT managers – have been seen in the past m...
Read more

FTTH - It's not just Fibre To The Home...

Image
  FTTH - So where is it exactly?                                                                                                                                                                            Although the question “What is FTTH?”  may be most commonly  asked by those unfamiliar with the technology, perhaps asking “ where is FTTH” might help more in the understanding of this fibre connectivity method. There seems to be some “unclarity” – for want of a better word - regarding the terms FTTH (Fibre To The Home) or FTTP (Fibre To The Pre...
Read more