Ask Me Help Desk - RJ45 splitter for one PC at a time

RJ45 splitter for one PC at a time

I would like to split one port of my router to two different wall jacks in different parts of the house. This is so I can use my laptop to either location without having to visit the junction box to enable the jack I want to use.

I am using an RJ45 passthrough splitter and thought this could work as long as only one wall jack is in use at a time.

What I have found is that it works only if one wall jack at a time is connected to the splitter.

In testing I have observed the following:
Either wall jack will work with either of the two splitter ports but only if the branch not in use is disconnected from the splitter. If you have a working connection, it will be disabled as soon as the unused branch to the other wall jack is plugged into the splitter. Windows reports "cable unplugged" when this is done. Unplugging the unused branch will restore functionality.
Again either wall jack will work with either splitter port as long as the other branch is not attached to the splitter.

At this point I doubt this can be made to work but I'm curious about what's happening here.

Sadly 2:1 doesn't go in my experience. You can add hub to your network allowing for more connections though. Simple and cost effective solution.

If I understand question, Could be capacitance, or unused line acting as antenna.
Or If you accidentally used a RJ 31X Jack, 8 pin just like computers, But are used for line seizure in Alarm Systems. If you open up jack, and see gold pins that make and break when pluging in.
It is a RJ 31X. Replace. If that doesn't work.
Router or Hub would solve.

The splitter is definitely affecting your electrical signal characteristics from the working jack as soon as you connect something else in the other jack.

What you need at a minimum is a hub instead of an RJ45 splitter. You can also get a simple switch. Plug the two wall connections into the hub/switch and then plug the router into the hub/switch. The Hub/Switch will serve as a gatekeeper of the electrical signals that come from each of your PC's. I say Hub or Switch because they both will serve the same purpose for you but if you are going to buy one I'd recommend a simple switch.

This of course assumes that your router accepts multiple hosts from a single port. Basically cable modem routers (or wireless routers) typically do allow for such a thing.

Most Cable Modem routers now-a-days have multiple ports on them which you can use (generally 4 ports is common). If your router only has one port then you might be better off purchasing a newer router that has the additional ports instead of the switch. The price difference is not that much and you'd be a lot happier I think.

Good Luck.

Cajalat, hope all is well.
I think? What he wants to do, and I have been curious before, but never tested.
Plug RJ45 splitter into modem, with cable in each, and with 1 computer, plug into 1 cable try it, if it worked in 1, should work in other, and if not, shouldn't work in other.
Second situation would be, Say you plug in a 10 foot cable into modem, place RJ45 splitter
at first computer location, with short(6') cable, then out of splitter with a 50' cable. To a second Location. With 1 computer can you plug into first location, and work, then unplug
computer, and then plug into second location for convience.
Question is, what can stop above from working? Capacitance? Unused cable acting as antenna?
Stonemason, Make sure the Jack is not an RJ31X used for Alarm systems for line seizure.
Pull off cover and see if it has pins that make and break, when plugging/unplugging cord.
Thanks, I have been trying Wireless N, with 4 ports, works great.

Quote:

Originally Posted by Stratmando

I think? what he wants to do, and I have been curious before, but never tested.
Plug RJ45 splitter into modem, with cable in each, and with 1 computer, plug into 1 cable try it, if it worked in 1, should work in other, and if not, shouldn't work in other.

The OP specifically mentioned connecting to a router. I've never even heard of an RJ45 splitter. If one wants to add more devices to a router they use a hub or, better yet, a switch.

ScottGem, hope all is well.
I have not seen done, but had been curious also. The RJ 45 is Like a RJ11 on steroids, have seen, do have.
The RJ45 is not meant for networking. It will parallel 2 lines coming off 1 device.(8cond.)
So if you had one computer, you could easily move between 2 places.
You are NEVER using more than 1 computer.
Electrically a network tester would easily verify pin for pin. And then to other location, verify pin for pin, I don't know poster did that. That could be problem.
If I get spare chance tomorrow I will give it a try, and respond here.
I, and I think poster want to know if anyone knows why it won't work, or, If it works at all.

OK, I think I understand now. You only want to use one at a time. My first thought is that it should work as you want it to. The fact that it isn't makes me wonder if the splitter is perhaps extending the cable length and creating an open end.

1. Have you tried to test the continuity of the connection when all three cables (the two wall jacks plus the router) from one of the jacks to the router?

2. Do you happen to have a link to the splitter in question?

I'm with ScottGem on this, I too haven't heard of an RJ45 splitter and now I'm curious. I'll dig to see what I find also.

I did a Google search and I just realized what you may have. I used those at home and in some locations at work. "Splitter" is a misleading term. What you may have is this:

Code:

PC1 RJ45-Splitter Single output - Pin 1 -Pin 1 - Pin 2 -Pin 2 - Pin 3 -Pin 3 - Pin 6 -Pin 6 PC2 - Pin 1 -Pin 4 - Pin 2 -Pin 5 - Pin 3 -Pin 7 - Pin 6 -Pin 8

What this does is allow you to share a single Cat5 cable for Two PC's by using the normally unused conductors (4,5,7,8) to carry the traffic of a 2nd PC. Then on the other end of the cable you have split the single cable back out to two cables so that you can connect into two ports on a switch like this:

Code:

PC1 \ /Port 1 RJ45-Splitter -----Cat5 cable in the wall --------- RJ45-Splitter PC2 / \Port 2

Maybe I'm off base but I think that might be what you have.

http://www.dataaccessories.com/R8026.GIF
This is a picture of what doesn't exsist, and like I say I have one, I am asking anyone who HAS SEEN, not HAS NOT. If you never heard of it does it mean it doesn't exist.
I am talking 8 conductor and splitter not to 2 4's.
Stonemason, I will test tomorrow and let you know the results.
http://dataaccessories.com/R8026.GIF

Quote:

Originally Posted by Stratmando

http://www.dataaccessories.com/R8026.GIF
This is a picture of what doesn't exsist, and like I say I have one, I am asking anyone who HAS SEEN, not HAS NOT. If you never heard of it does it mean it doesn't exist.
I am talking 8 conductor and splitter not to 2 4's.
Stonemason, I will test tomorrow and let you know the results.

OK, I see what you're talking about (picture says a thousand words). Although this has the casing of an "RJ45" it is NOT meant for Ethernet. This is a Telecommunication 8P8C T (8 Position, 8 Conductor) jack. It is an RJ45 splitter not an Ethernet Splitter. There is a difference.

The reason why only one cable at a time works when used for Ethernet is because as soon as you connect the other Cat5 cable (even though there is nothing plugged in on the other end) it creates an impedance mismatch and signals would reflect at the split rendering the connection unusable. It is as if you took a regular Cat5 and untwisted the 4 pairs of wires and put them an inch apart. That magnetic cancellation effect goes out the door and all sorts of induction/impedance is introduced into the picture which renders your cable unusable.

Stratmando... when you test make sure you have a long enough cable connected into the 2nd port. If you use a short cable it might not create enough of an impedance mismatch and might actually look like it worked but if you run a Cat5 tester on it chances are it will fail the impedance test.

The cable lengths I mentioned were random lengths. I could see where some lengths would be worse than others. Because of wavelengths.

Heylo everyone,
I also used same splitter today as needed to use teo laptops simultaneously through one LAN port but it doesn't work.

Any suggestions??

Anshu

That splitter is not meant for networking or 2 computers. You will need router, or something with more ports.
I didn't get a chance today to test if 1 at a time could work with splitter.
Will find out.

Thanks buddy, will wait for you response.

anshubathla, this test is one computer at a time.
Do you need 2 computers hooked up, or curious also?

Quote:

Originally Posted by anshubathla

Heylo everyone,
I also used same splitter today as needed to use teo laptops simultaneously through one LAN port but it doesn't work.

Any suggestions???

Anshu

Did you read the posts in this thread? It would seem the question was already answered. If you need to add devices to a LAN, use a switch or hub.

Guys there a chip and good hub just 3 or five connection you can buy even 10 box and really working good RJ45 splitter is not good trust me it cause your connection slowing down

The splitter is a real device. Sometimes, what you will run into is TX/RX issue. The port on the switch/router needs to be able to handle both connections at once. You will get more collissions at times for some reason. Your speed will probably be limited down to 10MB regardless of the advertised router speeds on the ports as well. The splitters will not work on a Gigabit switch since they utilize all eight wires. Regardless of adverstisments, the splitters are also not rated at cat5. The splitter is a great device for a temporary solution. A long term solution is to go to your nearest Wal-Mart or BestBuy and get a dirt cheap D-Link 5 port switch for less than 30 dollars and run off the port instead of the splitter.

Thanks to everyone for your answers. I believe the impedence/capacitance/electrical characteristics at the split is probably the answer. However!. I have since learned than my IBM Thinkpad from work will let me get away with this. It will work as I had hoped, but my own Dell Latitude with a 3com card won't handle it. I have also successfully tested an old 166Mhz Pentium with a really cheap network card and it too works when the other branch of the splitter is connected. At this point playing around with this splitter is just a curiosity and I will install a switch in order to have a dependable solution.