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

Transcription

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 s 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. The will typically be installed on the outside of the home which includes an interface for customer cabling to be connected to it. RJ454 data outlets RJ12 or screw terminals for telephone s F connector for TV provided by NBN Co. PSU FIGURE 1 SHOWS THE MOST LIKLEY LOCATION FOR AN EXTERNAL AND ASSOCIATED INTRFACES The challenge is how to connect the customer cabling to the. 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 s 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 s 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 s delivered by the NBN Co. network connected to the existing cabling. Let s first look at how many s are currently connected in the home at this stage.

2 Voice and Typical daisy chain 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. 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. GPO for PSU ADSL filter 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 to other phone outlets and possibly the broadband modem. Television Free to Air Typical free to air TV installation FIGURE 3 TYPICAL FREE TO AIR TV INSTALLATION Figure 3 shows a typical installation connecting the television antenna to the televisions.

3 Television Pay TV 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 s in the home phone, data, free to air TV and Pay TV. Let s now look at the process to connect the s being delivered by the NBN Co via the. Since the can delivering: Voice RF Free to Air TV and pay TV We shall look at all three. There is a possibility that the is installed internally, if this is the case this will not change the need to interface with the existing cabling. Typical daisy chain ADSL filter provided by NBN Co. Existing carrier interface between external cable and internal cable. This is not a network boundary point. PSU FIGURE 5 SHOWS THE LOCATION OF THE AND EXISTING VOICE DATA CABLE Figure 5 show the on the outside wall and the typical voice and data cabling. Now let s look at the interface in more detail.

4 The interfaces provided on the see Figure 1 may vary but typically will be Service Voice TV Interface Voice interface is either an RJ socket or screw terminals. You will find between 1 to 4 voice interfaces depending on the being installed. interface is an RJ45 socket. You will find between 1 up to 4 data interfaces. 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 from the to the existing phone cabling we need to run cabling from the s voice interface to a point adjacent to the network and install a new socket, see Figure 6. Move the customer cabling from the existing network 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. Typical daisy chain provided by NBN Co. Existing carrier interface between external cable and internal cable. This is not a network boundary point. PSU ADSL filter Telephone Existing customer cabling move to newly installed socket FIGURE 6 EXTENDING THE DATA AND VOICE SERVICES FROM THE Now we need to look at connecting the data. The data port on the 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 data port will need to be extended to the switch as just another Ethernet device.

5 Typical daisy chain provided by NBN Co. Existing carrier interface between external cable and internal cable. This is not a network boundary point. PSU ADSL modem and filter are removed Telephone Existing customer cabling move to newly installed socket FIGURE 7 EXTENDING THE DATA PORT ON THE TO THE EXISTING COMPUTER Finally Television, if the is also going to be provisioned to delivery Free to air and Pay TV then you need to extend the Television (RF) port. TV Set top box for pay TV provided by NBN Co. RF splitter Connected to new phone PSU 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. At this stage one of the challenges that exist with the cabling for the data and to a lesser extend the phone is having to field terminate the RJ plugs onto the cabling so they can be plugged into the 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 to the computer network. For this reason the Smart Wired Consortium has proposed the concept of a universal interface which allows all three s from the to be extended to a device that uses IDC punch down connectors for the customer cabling and factory supplied patch leads between the Universal interface and the.

6 Secure housing for O N T Smart Wired Universal Interface From To Customer Cabling Voice Elec Meter Factory terminated leads of various sizes Video (RF) IDC terminations for voice and data 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 s from the is a breeze. On the other hand the work required to retrofit the incoming s from the to the existing customer cabling or to connect directly to the required devices requires proper planning as it is difficult. By Ian Milner for Connections Magazine, July 2010.