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Problems with RJ45 termination(please help asap!!)
chugg Apr-22-00 02:28 AM
Ok....I have ran some cat5e 350mhz cable in my house, all of the cables run into a 110 patch panel in a central location. The other ends all go to diffrent rooms. I have made SURE EMI and exceeding the maximum length of the cables are NOT a factor. On the patch panel the 110 block is color coded like so:

white/blue
blue

white/orange
orange

white/green
green

white/brown
brown

I have "punched down" the ends of the cables into the 110 block just like they are color coded. Now on the other end of the cable I have terminated it with standard Rj45 connectors using the same color pattern as described on the patch panel. I have a cheap LED based remote tester that I used it says all the wires are connected but "not a parallel cable". I have made lots of standard parallel patch cables and it checks all of them out as being a "paralell cable" and it works fine. I have even disregarded the cable tester and just pluged the cable in....I get NO link light, I have also tried to flip the sides (instead of starting with white blue and ending with brown, starting with brown and ending with white blue)The tester still says not a parallel cable and the link lights do not come on...

I HAVE read your article and do not know if I should try the 568-a and 568-b standards because they do not make sense due to the fact that they are NOT connceted like that on the patch pannels.

Thanks,
William


1. RE: Problems with RJ45 termination(please help asap!!)
lbyard Apr-22-00 03:55 PM
In response to message 0
William, If it were my house, there would be no 110 block and no wall jacks. I would run the cables straight from the hub to the PCs. And, I would have a less complicated, more reliable, and easier to troubleshoot network. In my house, the cables would run through the basement and through a hole in the floor to each PC. (Do not use staples to secure the cables to the rafters or use anything which will deform the cables). All of he other ends would run through a larger hole to the hub, if it were not located in the basement. I have wall-to-wall carpeting through-out and that method would work fine. Hide everything behind furniture and do it while the wife is out shopping. So, your wife won’t let you drill holes through “her” nice hardwood floors? In that case I would install wall jacks. But, I still would not use a 110 block for a small network—no way. Wall plates are available which can accommodate up to six RJ-45 jacks for the hub end. Need more? Install another outlet box (there are flush-mount adapters to install wall plates over holes in the wall without using outlet boxes, surface-mount boxes, etc.). The jacks I use (ICC 1C1078E51V CAT 5E) are nicely color-coded for dummies for both the 568A and 568B standards. You can wire them for either color code as long as the ends are identical (see Let’s Make it Simple: http://duxcw.com/digest/Howto/network/cable/cable6.htm). Use standard straight-thru patch cables of either type, 568A or 568B. It makes no difference which you use and they can even be mixed if like being confused. “The electrons couldn’t care less” about the color of the wires from one end of a patch cable to the other. All they care about is that the wires connecting the T+ and T- of the transmitter to the R+ and R-, respectively, of the receiver are a twisted pair and that the T+ pin is connected to the R+ pin, etc. (for a picture, see the top of http://duxcw.com/digest/Howto/network/cable/cable5.htm). Each end of an Ethernet pipe has a receiver and a transmitter and the pipe uses two of the four twisted pairs.

No, one does not terminate an RJ-45 like the 110 block. It is terminated using the 586A (preferred) or 586B (acceptable alternative) standards. The active pins on an RJ-45 plug are 1, 2, 3, and 6. In a straight-thru cable used to connect a PC to a Hub (or Switch) pins 1 and 2 at one end are connected with a twisted pair to pins 1 and 2 at the other end. Your wiring scheme does that with the blue pair (and blue works just as well as the orange or green pairs for those pins). However, pins 3 and 6 (they are not adjacent) at one end and pins 3 and 6 at the other end should be connected with wires which are twisted around each other—the same pair (if you are a non-conformist and don’t like standards they can be any other pair—its your house). The 110 block scheme does not do that. You are using the white-orange wire from the orange pair to connect pin 3 to pin 3 and the green wire from the green pair to connect pin 6 to pin 6. If you are using standard patch cables from the jack ends to the PC’s, than everything is mismatched end-to-end. The very ends have to be identical and the intermediary connections have to connect like-wires.

If you are going to use the 110 block, it makes no difference what colors are on the block. Punched-down the way you have them is correct. The important thing is that wires coming from one PC cable are connected to like-colored wires coming from the other cable going to the PC’s port on the hub: white-blue to white-blue, blue to blue, orange-white to orange-white, orange to orange, etc. (although the first two are not actually used). All the block is doing is making two cable segments into one cable. Visualize it this way… If you cut one long, working cable, connecting a PC to a port on a hub in half, and join it back together with a 110 block, then you must reconnect the same wires which were joined together before you cut the cable in half. It is important that the untwisted ends of each twisted-pair at the RJ-45 plugs and jacks, and at the punch-down block do not exceed ˝.” I use a multimeter to check cable continuity, but that or a simple tester will not check the cable’s characteristics at Ethernet frequencies, and I rarely resort to using it. The important thing is to really understand and visualize how the cable should be wired. With that understanding, a cable that doesn’t work on a leg that worked before with a different cable usually has a bad end. I visually check ends first to see if I can identify which one it is. If I can’t see it, I use a divining rod to find and replace it: cut-off one end (the one I “feel” is wrong) and replace it, and if that doesn’t fix the cable, cut-off and replace the other end. I hope I did not confuse you more… Larry


2. RE: Problems with RJ45 termination(please help asap!!)
chugg Apr-22-00 09:25 PM
In response to message 1
Well even before you posted your reply I went down and tried the 568-a standard it worked great! No one ever said that between the 110 block and the female rj45 port on the other side it switches the wiring internaly to the 568a standard....Why dont they just make it so the 110 block is color coded to the 568a standard? It would have saved me an ass load of time.

As for not using the patch panel I used it because I am connecting 46 ends (EVERY room in my home is connected to my LAN including the bathrom kitchen and multiple ports in the larger rooms.) This makes it very easy to connect a laptop to the net via a proxy server no matter where I am.

Thanks for the help larry,
William


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