changing dsl modem from 8 pin to 4 pin RJ-11 plug

keithhr

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my original dsl wall plug used an 8 pin ethernet style cable plug to my old modem. My adsl provider sent me a new modem which included only a standard 4 pin RJ-11 cord with an 8 pin ethernet cord to go from modem to computer. I plugged it into my dedicated old plug(4 pin to 8 pin plug) and it didn't work. I took the jack off the wall and noticed that it only had two wires, a white and red wire attached to the plug which I detached from the wall. I plugged my new modem into a separate phone plug next to my fax machine and to my surprise it worked but slower than my old dedicated wall plug.
I went to radio shack and bought a new wall plug to hook up the standard phone cord to but it has wiring for 4 wires. I'm confused about how to hook up the two wires that currently work (just to make sure I didn't accidentally disconnect other operating wires, there are many more not connected, I hooked up my old dsl modem to this separate plug and it still synched.) to the new plug which has
red
green
black
yellow
wire connectors inside the plug.
new plug has 4 connectors and I seem to need only 2.
 

drizzle

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

keithhr,

I'm confused by your post.

Are you saying that your old set up had the telephone line with 8 pin plugs? I've never seen that for a home phone system. I've only seen 4 pin plugs.

As for the color coding you saw: the primary pair are red-green and the secondary are black-yellow. I have no idea what the red-white pair are. Is it possible that the white is a faded or very light green?

Probably the reason that the modem worked but slower when you used the other plug is, it sounds like when they installed dsl in your house they left one dedicated, unfiltered circuit for the dsl and put a filter in line for the rest of the house. If that's the case your modem was working through a filtered line and was probably losing lots of data.

If it were me I would try hooking the red wire to the red and the white to the green and see how it works. But that's if it were ME. I don't know enough to tell you for sure it won't damage your modem. I would take the chance if it were my modem but I wouldn't try this if I were helping a friend. I would try to find out more first.

Hope this helps.
 

keithhr

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

when they originally installed my dsl line, they put in a wall jack that was an 8 pin plug. That line came direct from the pole to my covad box and direct to my dsl plug. I was told at the time that it was a separate line and I assumed that I couldn't hook up my dsl modem to any other plug.Apparently they have since gone to modems which use a standard 4 pin plug and standard 4 pin wire. When I say it's slower, it's only slightly slower, but I'm kind of compulsive and want to use the original jack for what it was intended. Your suggestion to hook up red to red and white to green is an excellent one, worth a try on Monday. There are a total of 6 or 8 wires in the origina bundle coming out of the wall and I thought I had accidentally disconnected some until I hooke up my old modem to the dangling plug and wire and to my surprise it synched.
 

Thertel

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

this is pretty normal, in my old area. Its just plain laziness on the part of the dsl provider. They simply had cat 5 cable and a cat 5 wall jack in southern engineered it. Phone lines are only 4 lines, with typically only 2 being needed per circuit. Simply get a new telephone wall jack and connect the red and white wire to the two center terminals of the plug. If it works you got the wires in the right order if not reverse the wires. That should solve your problem altogether.

Damn lazy phone companies.
 

gadget_lover

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

An 8 pin rj-45 jack is sometimes used for 4 line jacks. The pin-out for a USOC 4 pair jack is....

pin signal
1 - t4
2 - t3
3 - t2
4 - R1
5 - T1
6 - r2
7 - r3
8 - r4

R1 and T1 are the signal for the first line.
r2 and t2 are the signal for the second line.
and so on.

They may have used an rj45 jack just to make sure people did not plug the DSL modem into the filtered jacks.

When they say "seperate line" it should be 100% disassociated with the main line. It sounds like it's really the same line with a second set of wiring.

Good luck.

Daniel
 

Thertel

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

Thats true but the odds of seeing that in a residential drop are just way to slim from my experience. You are more then likely right on the seperate line issue as well.
 

keithhr

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

they originally ran the dsl separate from the main line. However I can now hook the dsl to another phone jack that has been split too many times. I was surprised that it worked with just the regular phone line. I will try wiring the red and white from the wall jack to the new plug. If it works it would be really nice. One thing for sure, when anyone has a problem, like this or whatever, people are very kind to volunteer information and to try to help. It is still the spirit of the cpf that is special.
 

gadget_lover

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

I actually live within 100 miles of keithhr, and have the same phone company.

At one time I had a main line, a fax line and a second voice line. I had DSL added with the second voice line. They put in an RJ45 with all 3 lines in it as part of the installation. I re-did it myself later, making a straight run from the demark (that box outside the house) to my computer room for the DSL line, and a seperate run that had a DSL filter for the voice lines.

I have the same setup for the cable modem. One cable run directly from the splitter to the computer, the other goes to a distribution panel where all the TVs are connected.


Daniel
 

keithhr

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

I tried connecting the two wires coming out of the jack to the red and green connectors then the black and yellow, then reversing everything and couldn't get a sync out of my modem. The old connector inside the jack is a cat5e and now am at a loss.
 

gadget_lover

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

Keith, the wire going to your DSL modem has to match the wiring to the jack.

If your new modem (with the RJ11 plug) will sync using the other jacks in the house, it's using the center two contacts. That just happens to coincide with the USOC wiring for an RJ45 with 4 pairs.

The DSL line has dial tone, so you should be able to hear it when it's wired correctly if you plug in a regular phone. The Red/Green pair is the one you'd normally use.

You are using the new modem, right? And the only jack that does ont work is the one that used to heve the RJ45, right?

Daniel
 

keithhr

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

the one that used work the rj-45 doesn't work now when I wire it with a new plug. I tried the green and red connections in the new RJ-11 plug but it didn't work. I pushed the reset button on the modem each time, maybe I should have powered them down each time. I took the new plug back thinking I would try another brand, so I don't have a repacement jack at home for the moment. The oringal wiring is a white and orange wire which worked again when I hooked up my old modem to it with the old 8 pin plug.
 

gadget_lover

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

White + orange normally goes to pins 3 and 6 in a cat 5 cable.

To use the old jack with the new modem you need to translate the pairs in the cable back to the correct pins. Pins 3 and 6 in the RJ45 may not be the same when it gets to the other end.


You can give me a call if you wish. Maybe I can talk you through it.

Dan
 

James S

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

I haven't followed this thread much as there seems to be a lot of discussion about what should be a simple topic /ubbthreads/images/graemlins/smile.gif

The only wires you need are the 2 in the middle. You only need 2 wires, the center pair from the wall connected to the center pair in the plug on your DSL modem. I don't honestly know if it matters which goes to which, but if you wire it up one way and have problems or slow speed, swap them. Make sure if you use a twisted pair cable (and I would) that you make sure the middle pair is twisted together, and not twisted with other unused wires as that has the potential to pick up noise.

Thats all /ubbthreads/images/graemlins/smile.gif Now if you're worried about filters and the like, thats another topic.
 

keithhr

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Re: changing dsl modem from 8 pin to 4 pin RJ-11 p

thanks to James and all, for the responses. Daniel filled me in on everything I needed to know to have a shot at this.
 
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