Thanks, my 5 port is mounted inside the stem, I never need to go in there.

Sorry for all the questions but just to be sure before I order everything do I need the junction b boxes if I intend to run the cables directly into the 5 port in the stem?

I'm still not understanding the purpose of the b junction-are they used as a cable extender?

Thanks mate

It can be used as an extension and also a kind of wire splitter/hub junction like how a cable tv splitter works or a powerstrip to get multiple items plugged into 1 single power outlet.

Example as I recently upgraded my TT bike to Di2 running with a 3 port Junction A. Parts were: 2x bar end shifters, 2x brake shifters combo, FD, RD and battery. That is 6 total items that need to get connected to the Junction A in order to have the whole system working and the math doesn't work out this way. In order to get my system to work for all of the pieces I connected a few of them to 2 different Junction B's (each 4 port ones) and then 1 cable from each of the B's to the A. Even if I went with a 5 port Junction I'd still need at least 1 Junction B to get it to work.

So I actually wired mine as follows:

Left bar end shifter, FD & battery to Junction B #1 + 1 wire to Junction A
Right bar end, right basebar shifter & RD Junction B #2 + 1 wire to Junction A
Left Basebar shifter directly to Junction A

I might've transposed the left/right basebar shifter on which on actually plugs directly into Junction A though but you should get the gist of it. I personally chose the MT800 Junction A because it has built in wireless/bluetooth and a digital display for gear, shift mode and battery charge level. Worth it to me despite having to run extra wires and 1 additional Junction B over a 5 port Junction A (and trying to remember the light flashes for battery level or having to get a separate wireless unit which means more wires and connections to account for).

I needed them because I used 3 port. I also needed for length due to where I mounted.

If you use 5 port in stem you should not need the 2 b junctions at bars, just one at BB. The only thing I would double check is wire length of 9150’s.

Cheers.

Thanks I think I'm starting to get there. I don't understand though why ktm550 needed to use two b junction? Couldn't be have just used 1?

So basically I should just be able to buy the R9150 and run each into the spare ports in the 5 junction A and be done? And if they are long enough I could just use some jc200 cable joined a to add another length of cable?

Let me get something straight, I believe the P5-6 is just bar end shifters, FD, RD and battery correct? Your setup is a 5 port junction A correct? How is your system connected? Is it
1) FD/RD/Battery and 2x bar end shifters all directly plumbed with individual wires to the Junction A (taking up all 5 ports)?
or
2) Some of the ports on your Junction A are free (say 3 of 5 are connected for example)...there are few possibilities but I'm not going to guess your setup for you.
3) Something completely different (4 of 5 connected or something else I didn't list).

Tough to say what you exactly need unless I know what else you have in the entire system honestly. You could get away with just cables and 2 JC200 connectors or maybe you can't and require a 4 port Junction B and combo of cables/JC200 connectors too.

I can't speak for ktm550 but I assume because of the 3 port required 2 Junction B to get everything connected is kind of like how my setup is requiring 7 devices in total to connect with only 3 ports available in Junction A (and I just realized I miscounted my setup requirements in my earlier post). It just wouldn't work with just 1 Junction B because he'd be 1 connection short as "A" Ports 1 & 2 single devices directly and Port 3 connected to "B" which also has 3 devices directly connected. That accounts for 5 devices connected which leaves 2 devices the "odd ones" out (figuratively speaking). Edit: There is one way to get this to work but that would require a Y-Cable with 2 JC200 to work on 1 Junction B (4 port) and get 7 total devices to work on a 3 port Junction A (but to know or decide on if a Y-cable or JC200 is the route to go is why it is key to know your setup and help plan your routing).

1) Im not sure-3 of the 5 ports are taken up but Im not sure by what.
2) Correct, 3 of the 5 are connected

Man this is confusing huh..

Gotchya I think. Why would I still need a b junction at BB? With two free ports wouldn't each cable just go straight into each free port?

B junction at BB = 1.RD, 2.FD, 3.Battery, 4.Cable to one of the 5 ports in junction A in the stem.

Sounds like you have 2 ports free and you could just get away with the remote shifters directly plugged into them (if the remote shifter cables aren't long enough to reach you junction then you'd require 2x JC200 extensions and the necessary cables with sufficient length to get there). I am thinking your FD/RD/battery are probably all connection to its own Junction B near the BB area and then run up to the Junction A up top with the bar ends directly routed to the Junction A from the info you are telling me.

Thanks for all your help guys, I'll keep you posted how it turns out!

So how did it turn out?

I'm starting this experiment again. How to get single gear changes on each side of the base bar. Happy to run Syncro. What the latest best buttons etc. Any help appreciated

Thanks :)