In our local group recently there has been some confusion and questions about how Fusion, Wires-X, YSF and FCS works.
I hope with this post to make it a little clearer. Neither MAWCG or FARG have a fusion repeater but our close partner FARC does.
However, we do have a YSF server up and Running.
Before bringing in the diagram, lets talk about a couple of terms that we will be using:
C4FM
C4FM stands for Continuous Four Level Frequency Modulation and is a FDMA (Frequency Division Multiple Access) modulation method.
Ok, enough of the big words. C4FM is a digital modulation technology. What your radio uses over the air to talk digitally to other digital radios and repeaters.
Fusion
This is the name that Yaesu has given their implementation of C4FM. The full name is really System Fusion. It is not a new technology but a marketing term created by Yaesu for referring to their C4FM.
You can learn about System Fusion on the Yaesu website here: http://systemfusion.yaesu.com/what-is-system-fusion/
Wires-X
Wires-X is a technology that runs on top of System Fusion. It provides a network of repeaters. Wires-X has a concept called rooms where multiple repeaters and nodes can connect and talk to each other. A room is similar to a reflector in D-Star, a Talk Group in DMR and a conference in Echolink.
Wires-X provides a directory of connected rooms and manages the connections from Nodes/Repeaters to each room.
In addition, Wires-X provides a way from the radio to change to a different room, search rooms and more. Some radios have more features than others because of touch screens, etc.
There is also the ability to send messages and pictures, put them in a common message store on each node or room for others to read (think of news).
Without Wires-X, System Fusion is just a communication protocol.
YSF
YSF short for Yaesu System Fusion really is not a Yaesu technology when looking at the YSF servers. It is another method of creating a room where other System Fusion users can connect together.
Unlike Wires-X, there is no central management of the rooms that are up and available. There are directories of YSF servers (for example: https://register.ysfreflector.de/ and many of the digital softwares you run on your computer also maintain lists for easy selection.
The important thing to note is that System Fusion repeaters cannot directly access these servers. To get from Wires-X on Yaesu System Fusion to a YSF server, you need a bridge (more on that in a bit).
You can find YSF rooms connected on some repeaters that are running the MMDVM software as their repeater controller. Some of you may also know it as Pi-Star which is a pretty interface over the MMDVM software.
FCS Servers
FCS servers were originally created for use with DV4Mini. They have really grown since their creation. The FCS servers can hold multiple rooms on a single server and rooms were added quickly as the DV4Mini became popular.
They are now used by more than just the DV4Mini. It is my understanding that the each server can handle 99 rooms. That is why you have 3 different FCS servers for America Link. FCS-190 is on one server, FCS-290 another on and FCS-390 on another.
Like the YSF servers, the FCS servers cannot directly connect to Wires-X. This means there is a bridge that connects them together.
Bridge
A bridge is a way of connecting 2 different protocols or technology together. It is similar in concept to a cross band repeater that for example takes in a signal on 2 Meters and transmits it back out on 70cm.
Since YSF cannot directly talk to Wires-X, there is a bridge that can talk to both YSF and Wires-X. When it hears something on Wires-X it sends it to YSF and the opposite happens when it hears something on YSF.
There are multiple ways you can bridge between the networks. I am not sure of the technology that is being used for YSF or the FCS services for America Link.
One method is simply setting up a Wires-X node with a radio and setting up a YSF/FCS node with a radio on the same frequency. Very similar to what cross band repeat does.
There are some that may be able to make the translation using software. For example, a our XLX reflector translates from Brandmeister DMR TG 31241 to XLX336 Module B all in software digitally. It never decodes the audio.
That is possible because both use the AMBE2 format. For example, if you wanted to take the same DMR and put it on D-Star you would need to drop it to audio first and back because D-Star uses the older AMBE protocol.
Since Fusion, YSF and FCS are all using AMBE2, it can be done easily in software.
One last note on bridges and the diagram below. I have represented the bridges as between Wires-X and YSF as well as between Wires-X and FCS. It is possible that there is a bridge between Wires-X and YSF and then one between YSF and FCS with no bridge between FCS and Wires-X.
This would mean that when someone keys up on A Wires-X repeater, it would connect to YSF via a Bridge and then YSF would connect with FCS through a bridge.
It can get very complicated and it is important to remember that every bridge adds delay. Too much delay and people are talking over each other.
Diagram
Narrative
Wires-X / System Fusion
Lets look at the above diagram and talk about the different parts.
On the left side is a small representation of the Wires-X and Yaseu System Fusion cofiguration.
There is a network called the Wires-X Network that is represented by the cloud. This network runs across the internet but the cloud represents the members of the Wires-X network.
Connected to this Wires-X network are nodes. Nodes connect to repeaters and provide the connection from the repeater to the Wires-X network.
Every Node has a number and has its own room. For example, the K3ERM repeater in Frederick has a room that is 30386. Anyone can connect to it and talk to other that are connected to it.
America Link is the same thing, its room number is 21080. It could be a stand alone node with no repeater or it could have a repeater attached to it.
When I looked a little bit ago, there were 96 nodes / repeaters, like K3ERM in Frederick, connected to the America Link room.
While we are on this side of the drawing I want to clear up another item. At the top where the radios that are connecting to the repeater notice that they are communicating using System Fusion which is just Yaesu’s implementation of C4FM.
It is possible to setup a Wires-X repeater in FM only mode and talk to Wires-X. You lose all of the features of Wires-X digital mode like listing rooms, etc. You can still change rooms but it is done via DTMF.
Many rooms do not want FM in their rooms and most repeaters use Fusion. Some people use FM on their local node to connection to fusion.
YSF
On the top right of the drawing you have a YSF server. These servers do not need to be very powerful. Some run them in their homes on old computers. Our YSF server is running in the cloud in Atlanta, GA.
A YSF server is basically the same thing as a room except it is not connected to Wires-X. MMDVM and many pieces of software (IE. BLueDV) can connect directly to the YSF rooms.
YSF servers have dashboards similar to d-star and XLX reflectors. Here is ours for example: ysf.mawcg.org.
You will also notice a bridge connecting YSF to Wires-X. I do not know how America Link is linking everything together. The bridge represents that there needs to be something in between to connect them together.
I have heard a couple of people say that America Link is not working because there is a different conversation on Wires-X America Link and YSF America Link.
If that bridge between the 2 goes down, they are no longer connected making each of them their own Island.
FCS
There is probably not much more I can say about FCS that I did not say in the YSF section above.
FCS creates a “room” just like YSF. There are some differences in how it is implemented and maintained. For example, anyone can setup a YSF server and they also have to maintain it.
Unless things have changed, these servers are managed by a group and not available for anyone to create them.
I also want to note, as I said above, I do not know how things are linked but the same thing applies if there is a bridge disconnect or failure.
Final Thoughts
I hope this cleared up some confusion and made things at least a little clearer than mud.
With different system integrated together there is always the possibility of failures that are impacting. From my experience with Wires-X over the last few years, it has become very stable within its own ecosystem.
There are some other neat features that System Fusion offers like group mode, etc. If you own a Fusion capable radio I suggest looking into some of the other features.
