Note: The stuff below applies to
optical network or AON.
Freedom internet also uses Passive optical network or PON, such as GPON and XGPON.
The link is a single strand of
fiber, with a different infrared laser wavelength going in each direction.
A splitter prism inside each transceiver separates the two wavelengths;
|To network (Up)||From network (Down)|
|IEEE 802.3||IEEE 802.3|
|TX: 1310 nm||TX: 1490 nm|
|RX: 1490 nm||RX: 1310 nm|
Note that this in fact an IEEE Ethernet standard!
PON, on the other hand, is an ITU standard.
And infrared is of course, radio waves with a very short wavelength;
|1310 nm||229 THz|
|1490 nm||201 THz|
|1550 nm||194 THz|
In theory, any fibre-optic media converter which meets the above specs
Note that the SC/PC and SC/APC are incompatible; The APC has a slanted / angled tip;
AFAIK PC and UPC connectors are compatible. But don't mix blue and green plugs!
The fibre-optic cable is terminated at a FTU (Fibre Termination Unit); A little spool with some fibre-optic cable and a clamp which holds a fibre-optic connector. Mounted on the FTU is either a NTU (Network Termination Unit) or a patch cover. A NTU is a fibre-optic media converter which is mounted directly on the FTU.
At my place, a ZTE ZXHN F3100 fibre-optic media converter is installed
(powered by a 12V, 1A DC adaptor);
Note that there are different versions of this NTU. The older version has a different appearance and fibre-optic connector.
A patch cover has a fibre-optic patch cord.
Note that the above patch cord has two SC (big) connectors. And a lot of equipment requires a LC (small) connector.
A media converter converts optical to electric and vice versa.
For instance to a TP-LINK MC220L media converter;
Some routers and media converters, including the MC220L, require a separate
form-factor pluggable transceiver (SFP), which plugs into the media
There are different SFPs for the various infrared wavelengths.
You may need a SC/PC to LC/PC adaptor cable or a SC/APC to LC/PC adaptor cable in order to connect to a SFP.
Apparently, there are also SFPs that take a LC/APC fibre-optical connector (small green plug). So there are four types of fibre-optic patch cords;
|Big plug||Small plug|
Big and small are relative. Both plugs are rather small. The ferrule (the ceramic tube which holds the fibre) is 2.5 mm wide in a SC connector and 1.25 mm in a LC connector!
Make sure to use the right patch cord!
Some people use the phrase 'fibre-optic modem'.
Though a media converter can be considered to be a ca 200 THz ASK (on-off amplitude modulation) modem, it is never clear what people mean by 'fibre-optic modem';
Is it a media converter? A router? An analogue telephone adaptor? Any combination thereof? Or anything (indirectly) connected to a fibre-optic link?
It is best to be clear. So the confusing phrase 'fibre-optic modem' should be avoided. Most fibre-optic links are in fact a type of Ethernet. So to avoid mystification and confusion, it's best to treat it as such.
Equally confusing is the acronym ONT; 'Optical Network Terminal'. ONT can in fact mean many totally different things! Always ask people what exactly they mean by ONT!
AFAIK, Freedom Internet uses the acronym 'ONT' exclusively to mean 'PON media converter'. Nothing more. So no router or ATA (Analogue Telephone Adaptor).