ONT FIGURE 1 SHOWS THE MOST LIKLEY LOCATION FOR AN EXTERNAL ONT AND ASSOCIATED INTRFACES

Download (0)

Full text

(1)

Connecting to the National Broadband Network

One of the greatest challenges facing telecommunications carriers around the world has been what is known as the last mile, the bit of copper cable between the telephone exchange and the home. We must say this copper cable has served them well as they have been able to develop technologies to allow the delivery of Broadband services with speed up to 12Mbps (this speed varies depending on proximity to the exchange and geographical location). It should be

mentioned that between the telephone exchanges all connectivity is fibre with huge capacity so there is not problem in getting very high speeds signals to your local exchange. We are now starting to see a revolution as countries around the world start to seriously consider and in some cases install fibre all the way to the home. In Australia this is what is being proposed by the National Broadband Network which is starting to be rolled out by the NBN Co.

In short the NBN Co. will deliver a fibre optic cable to your premises and install what is know as a Optical Network Termination unit ONT. The ONT will typically be installed on the outside of the home which includes an interface for customer cabling to be connected to it.

SB SDU

ONT PSU ONT

ONT provided by NBN Co.

ONT

RJ454 data outlets RJ12 or screw terminals for telephone services F connector for TV

FIGURE 1 SHOWS THE MOST LIKLEY LOCATION FOR AN EXTERNAL ONT AND ASSOCIATED INTRFACES

The challenge is how to connect the customer cabling to the ONT. In this case we need to consider two cases:

1. New homes 2. Existing homes NEW HOMES

In new homes a cabling platform should be installed during construction to allow for the connectivity of the services offered by the NBN. The cabling platform required is fully specified in the Smart Wired® Cabling handbook

EXISTING HOMES

If the home is due for a major renovation it is recommended to treat it if at all possible as a new home and work to the specifications detailed on the Smart Wired® Cabling Handbook

If you are dealing with an existing home without any prospects of being renovated then it is hard work. Let’s look at the current way services are connected in existing homes without a Smart Wired® cabling system. We will find a myriad of ways and somehow we will need to get the services delivered by the NBN Co. network connected to the existing cabling. Let’s first look

(2)

Voice and Data SB SDU GPO for ONT PSU Existing network boundary socket

Typical daisy chain cabling for phones

ADSL filter Junction box, typically grey installed by

the carrier to connect the external lead in cable from the street to the internal cable to the network boundary socket. Note, this is only one possibility, there is also aerial cabling and underground cabling terminated directly onto a sockets or cabling from Pay TV networks connected via a Customer Access Unit (CAU) etc, etc.

ADSL Modem

FIGURE 2 VOICE AND DATA CONNECTIVITY

Figure 2 show one way the connection is made, you have incoming cable from the carrier’s network terminating onto some interface point which in most cases is not the NETWORK BOUNDARY and then the cabling being extended to the first socket. From the first socket you have customer cabling extending the service to other phone outlets and possibly the broadband modem.

Television Free to Air

SB SDU

Typical free to air TV installation

FIGURE 3 TYPICAL FREE TO AIR TV INSTALLATION

(3)

Television Pay TV

SB SDU TV Set top box

for pay TV

FIGURE 4 PAY TV CABLING INSTALLATION

In the above three figures we have an example of the most commonly connected services in the home phone, data, free to air TV and Pay TV.

Let’s now look at the process to connect the services being delivered by the NBN Co via the ONT. Since the ONT can delivering:

 Voice  Data

 RF – Free to Air TV and pay TV

We shall look at all three. There is a possibility that the ONT is installed internally, if this is the case this will not change the need to interface with the existing cabling.

SB SDU

ONT PSU

Existing network boundary socket

Typical daisy chain cabling for phones

ADSL filter

Existing carrier interface between external cable and internal cable. This is not a network boundary

point.

ADSL Modem

ONT ONT provided by NBN Co.

(4)

The interfaces provided on the ONT see Figure 1 may vary but typically will be Service Interface

Voice Voice interface is either an RJ socket or screw terminals. You will find between 1 to 4 voice interfaces depending on the ONT being installed.

Data Data interface is an RJ45 socket. You will find between 1 up to 4 data interfaces. TV TV interface which is more correctly referred to as and RF interface is an F

connector.

Figure 2 shows the existing cabling for the voice and data is actually the same 2 pair telephone cable. To extend the telephone service from the ONT to the existing phone cabling we need to run cabling from the ONT’s voice interface to a point adjacent to the network boundary socket and install a new socket, see Figure 6. Move the customer cabling from the existing network boundary socket to the new socket you installed. Note by doing the cabling this way we have not interfered with the existing carrier network boundary. What you will find in many homes is the carrier cabling comes in from the street into the carrier interface box where the cabling splits into three or more cables connecting directly to telephone sockets. In these cases each socket is a network boundary and you cannot touch the cable or the sockets.

SB SDU

ONT PSU

Existing network boundary socket

Typical daisy chain cabling for phones

ADSL filter

Existing carrier interface between external cable and internal cable. This is

not a network boundary point.

ADSL Modem

ONT ONT provided by NBN Co.

Telephone service Data service Existing customer cabling move to newly installed socket

FIGURE 6 EXTENDING THE DATA AND VOICE SERVICES FROM THE ONT

Now we need to look at connecting the data service. The data port on the ONT is an Ethernet port so what we need to do is connect this port directly to the computer. In Figure 7 you see the data port extended directly to the computer. This sound quite simple but the difficulty is getting the cabling in as this would have to be Cat 5 Cable or better. There are alternate technologies that can be used but any alternate will introduce more failure points. This example also looks at only one computer in cases where there are more computers the connection will probably be via a switch so the ONT data port will need to be extended to the switch as just another Ethernet device.

(5)

SB SDU

ONT PSU

Existing network boundary socket

Typical daisy chain cabling for phones

ADSL modem and

filter are removed

Existing carrier interface between external cable and internal cable. This is

not a network boundary point.

ADSL Modem

ONT ONT provided by NBN Co.

Telephone service Data service Existing customer cabling move to newly installed socket

FIGURE 7 EXTENDING THE DATA PORT ON THE ONT TO THE EXISTING COMPUTER

Finally Television, if the ONT is also going to be provisioned to delivery Free to air and Pay TV then you need to extend the Television (RF) port.

SB SDU TV Set top box

for pay TV

ONT ONT provided by NBN Co.

ONT PSU RF splitter Connected to new phone service

FIGURE 8 EXTENDING THE RF VIDOE PORT

Figure 8 shows the RF video port extended into an RF splitter and then onto the televisions and the Pay TV set top box. So instead of having one cable system for free to air and another for Pay TV the same cabling infrastructure will do both. If there is a set top box that connects to the phone line you will have to also connect the set top box to the new phone service.

At this stage one of the challenges that exist with the cabling for the data and to a lesser extend the phone service is having to field terminate the RJ plugs onto the cabling so they can be plugged into the ONT’s interfaces. Field terminated RJ plugs are notoriously unrelaiable and in the case of data could significantly affect the actual speed you get from the ONT to the computer network. For this reason the Smart Wired® Consortium has proposed the concept of a universal interface which allows all three services from the ONT to be extended to a device that uses IDC

(6)

Smart Wired®

Universal Interface

Secure housing for ONT

From ONT To Customer Cabling Voice Data Video (RF) 1 2 3 4 1 2 3 4 1 2 3 4

O

N

T

Factory terminated leads of various sizes IDC terminations for voice and data

Elec Meter

FIGURE 9 UNIVERSAL INTERFACE

This is a proposed solution to what is possibly a problem in the field.

In summary if you are today providing advice to clients building and renovating it is more important than ever that you adopt a Smart Wired® platform as this will make the interfacing of the services from the ONT is a breeze. On the other hand the work required to retrofit the incoming services from the ONT to the existing customer cabling or to connect directly to the required devices requires proper planning as it is difficult.

Figure

Updating...

References