There are a number of different types of phone sockets typically used for telephone points in Australia. In this article I’ll discuss them and how to choose which to use for your installation.
RJ12 or 6P4C
The RJ12 socket, also known more technically as a 6P4C is probably the most commonly installed in new homes. 6P4C means to 6 Position 4 Conductors. If you look at a plug to go into a 6P4C socket you’ll see that there are 4 metal prongs or conductors and either side of them there will be 1 empty slot where a conductor could go but isn’t. I would recommend these in most typical domestic installations where there is not extensive LAN cabling.
6P4C sockets are available in a number of different mounting options, such as wall plate inserts, full wall plates and fascia board mounts.
8P4C
These sockets are sometimes found in commercial installations but some home offices might have them too. Visually at a glance they will look like the RJ45 discussed next, wider than an ordinary phone socket, but with only 4 metal conductors inside. 6P4C, 8P4C and 8P8C plugs can both be used with them without any issues. I don’t really see much reason to go with this type in a home installation.
RJ45 or 8P8C
The RJ45 socket, also known as the 8P8C is the typical LAN cable socket. 8P8C means 8 Position 8 Conductors. The sockets and plugs for 8P8C are a bit wider than the ones used for RJ12 or 6P4C. Even though their typical use is for LAN cabling, you can use them for telephone points as well. If you are planning an installation of a home network with a central distributor I would definitely recommend using RJ45/8P8C connectors for all sockets in your home. In this way any socket could be used for either a phone or a LAN point. The only thing to note is that when using 8P8Cs for phones, you will need a special phone fly lead with an 8P4C plug on the end that goes into the wall and 6P4C on the end that goes into the phone. Ordinary common 6P4C phone fly leads will work, but over time will damage the 8P8C socket.
8P8C sockets are available in a number of different mounting options, such as wall plate inserts, full wall plates and fascia board mounts.
RJ11 or 4P4C
The RJ11, also known as the 4P4C is an uncommon type of telephone socket/plug that is used for specialist purposes. The are usually seen in association with alarm panels or music on hold devices. I wouldn’t use these unless there was a specific reason to. A 4P4C cable will plug into a 6P4C socket with no issues, but shouldn’t be plugged into an 8P4C socket for the reasons listed above.
4P4C sockets are usually only available as wall plate insert sockets.
610 Series Sockets

The 610 Series sockets are the traditional older style telephone socket, with the cream coloured square box with prongs plug that slides into the end of a similar socket. You’ll see them on many older homes, but up until recently they were also installed in some circumstances in newer homes. They come in a number of varieties including 610, 611 and 612. The main one to be careful to watch out for is the Mode 3 version. Mode 3 sockets are denoted by two semi-circles around the screw. These are specially designed so that any device connected to them can take over the phone line and disconnect any existing calls on the line. This was used so that alarm systems could have the ability to dial out to security services whenever they needed to. There are now Mode 3 sockets on the RJ12 variety so they’re no longer commonly used.
610 Series sockets are still available but I typically wouldn’t recommend them unless there is no other option such as in some replacement situations. In most cases though they can be replaced by a fascia mount RJ12/6P4C socket.