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  • #2172183

    Simple CAT5 data run just will not work?

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    by robo_dev ·

    I think I know the answer to this question, I’m just here whining……

    I ran a simple 75 foot CAT5 data run, punched it down to a Leviton CAT5 module on each end, using 568A pair sequence, and it just does not work.

    Got link light on both ends, but Windows XP status shows packets sent, but no packets received. So DHCP won’t work, obviously and neither does PING or anything else.

    Open pair, right?

    I hooked up my Test-UM LanRover cable tester, it shows PASS and the capacitance measurement is normal. I double checked it with the cable tester, even trying to wiggle the cables in case it is a bad connection. Nope. This cable is perfect.

    So my cable tester shows that it’s good, from end-to-end, including the patch cables. Tried swapping patch cables, of course.

    I get link light at both ends, have tested NIC and swapped ethernet router at other end.

    The PC can ping a device on a switch attached directly to the PC, but not the router on the other end, which is pingable. Of course the PC cannot get a DHCP address either.

    I plan to just re-terminate the CAT5 jacks….maybe something is not punched down cleanly???

    This is a standard 192.168.0.1 network, so I doubt I did anything stupid. Windows firewall is turned off, very plain-jane PC (security DVR).

    If all else fails, I pulled a second run of CAT5 cable at the same time, so maybe there is cable damage from installing the cable???

    I know, I know, I should have used wireless LAN!

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    Replies
    • #2809314

      Clarifications

      by robo_dev ·

      In reply to Simple CAT5 data run just will not work?

      Clarifications

    • #2809308

      Questions

      by netman1958 ·

      In reply to Simple CAT5 data run just will not work?

      Does the patch cable at the other end plug directly into the router or is there a switch first? That is
      PC -> patch cable -> leviton jack -> 75′ cable run -> leviton jack -> patch cable -> ? router or switch ?

      • #2810597

        Reponse To Answer

        by robo_dev ·

        In reply to Questions

        Tried it both ways, same result.

        This basic setup is a mini-rack that I setup and tested at my shop, on my network, and it all worked perfectly, with static or DHCP. I bring it to the customer house, run a simple data wire, and it decides to not work.

        Before I get out the diagonal-cutters and put new ends on the cable I intend to try:

        a) plugging a small ethernet switch into the router-end of the connection, just in case somehow the router’s ethernet port is just somehow flaky.

        b) plug in a ‘pair splitter’ Y-cable at each end. This is a device that lets you run two data runs over a single CAT5 run. Basically it will let me try using the other two pairs of the cable, assuming that I simply have a bad connection or a pair of the cable itself is damaged.

        I also ran a second wire to the jack, which is a CAT5E cable. My guess is if I simply give-up and punch down the second wire, it will work like a dream.

    • #2809307

      Other things to check

      by philldmc ·

      In reply to Simple CAT5 data run just will not work?

      If all lights show connection, I’m assuming on both the NIC and router..you might want to double check network settings, for example, did you program a static IP by chance? Is the NIC disabled, etc.

      In addition, I did run into a issue where a client had programmed their router to give only 1 IP address…maybe try resetting the router…

      • #2810595

        Reponse To Answer

        by robo_dev ·

        In reply to Other things to check

        Good thoughts.

        It works with neither DHCP nor static. I have a device in the rack with the PC (APC power controller), that I can ping or web-connect to, so I am confident that the PC and network settings are valid. I must mention that I’ve been working with networks for more than 20 years, but I do admit that I can make mistakes.

        The bottom line, I suspect, is that one of the punched-down connections is out of tolerance, and simply cutting off the connection and re-terminating the data run will fix it. Again, the odd thing is that my trusty cable tester says it’s a good cable

    • #2809305

      In addition to the above

      by oh smeg ·

      In reply to Simple CAT5 data run just will not work?

      Assuming that the Network is not the issue here have you checked for any possible Interference Sources that could be adversely affecting the Cable?

      I remember one run in a shop that caused an Interment issue, it drove me crazy till I looked next door and found a Dentist with their own X Ray equipment. Apparently whenever they took an X Ray of someones mouth the Network crashed.

      Not likely to be something like that but Power Leads inside walls can cause this to happen as well. Look to see if there is any 3 Phase Equipment on that cable run that is a dead give away for issues with CAT5. I’ve also seen normal Power Runs too close to network Cables cause this to happen and there have been numerous times where I’ve had to rerun CAT5 to get around this. Doesn’t affect Phone Lines anywhere near as much so if you get a person who pulls Phone Runs they don’t be as careful as Network Cable Pullers. 😉

      If you can not run the cable differently you may have to use Shielded Cable. Bit more expensive on the cost of the cable and connectors but it solves a lot of issues. 😉

      Col

      • #2810505

        Reponse To Answer

        by rahbm ·

        In reply to In addition to the above

        An “interment” issue? You are not supposed to BURY the cable , you know!

    • #2810590

      That’s an odd one

      by netman1958 ·

      In reply to Simple CAT5 data run just will not work?

      I was thinking that if you were plugging the patch cable directly into the router without a switch in between, you might need a x-over cable but if you have tried it with a switch in between that eliminates that. Let us know what you find out as this is an interesting one.

    • #2810589

      Hmmm…that may be an issue in this case

      by robo_dev ·

      In reply to Simple CAT5 data run just will not work?

      This data run is in a house, and I ran it through a crawl space where there are some power lines. I was trying to be careful about avoiding proximity to power cables, but maybe I messed up. I did run a shielded cable that I intend to hookup later for video. I also ran a spare CAT5 cable.

    • #2810572

      What kind of equipment are you using?

      by oldbaritone ·

      In reply to Simple CAT5 data run just will not work?

      Do you have a “real” punch tool, or are you using a plastic freebie included with the connectors? (Or worse, a screwdriver?) You get what you pay for, and freebies usually don’t do a very good job. If you’re running cable yourself, spend some of your savings to buy decent tools. You don’t need the most expensive ones, but get a middle-of-the-line tool at least.

      A simple continuity tester is not enough, and sadly they’re the most readily available, inexpensive ones. Does your tester verify correct pairing? Correct Polarity? The moderate-priced testers will test those too. My first guess would be to check the connectors with a magnifying glass, and inspect the connections, cuts, and colors.

      To test the cable completely, you’d need a TDR tester. It would find concealed cable damage as well, but it’s more expensive than most DIYers want to spend. It’s probably less expensive to pull a new wire.

      When you’re pulling cable, if you need to “yank” on it, STOP! You need to go find out why it’s jamming, rather than pulling harder. If you don’t, cable damage is likely. Kinks and small loops can be a problem in Cat5. And as several folks have mentioned, keep Cat5 away from power cables and high-energy appliances and equipment. Take a different route, and never run a data cable through an existing hole with a power cable.

      Based on your discussion that the computer works properly when plugged directly into the router, it does sound like the problem is in the Cat5 run.

      • #2810452

        Reponse To Answer

        by robo_dev ·

        In reply to What kind of equipment are you using?

        Excellent ideas. I admit that while I have a ‘real’ punchdown tool, but I used the little plastic thingie.

        I have a TestUM LanRover tester that seems to work OK…it can measure capacitance and distance, as well well as Pairing. Wish it had a lighted display, but I digress….

        I have miles of extra cable, and I ran a spare CAT5E cable between the two points. I will post the solution when I find it.

    • #2810541

      have you tried 568B ?

      by cg it ·

      In reply to Simple CAT5 data run just will not work?

      while every cable guy will say 568A works, and it does, everything has to be wired 568A. So the biggest problem is all premade patch cords are 568B. so you hook up a 568A to a 568B what do you get? cross over cable. while there’s link, maybe, and it will test fine with the lan tester, cross overs don’t work on PC to switchports.

      • #2810492

        Reponse To Answer

        by davidmblackwell ·

        In reply to have you tried 568B ?

        If both ends of a link are 568A, or both ends are 568B, then you have a straight-through. Doesn’t matter if you use two straight through links, one using 568A and the other using 568B. The electrons don’t care if the plastic around the wire is orange or green. You only get a crossover if one end of the same link is A and the other is B.

        To address the original problem, EMI, faulty termination on the cable run, wire fault somewhere in the cable maybe it was damaged during installation? Since the equipment (I assume including the patch cables, otherwise add that to the list) all tested out before being connected to the cable run that is where I would be looking for the fault. It could have been damaged during the installation I’ve seen that happen many times in different ways.

        Is this gigabit ethernet? If so, it uses all four wire pairs rather than just two. I’ve seen a few problems there that allow the initial negotiation to succeed but cause faults during transmission, or some devices that just won’t step down to the slower speeds.

      • #2810454

        Reponse To Answer

        by cg it ·

        In reply to have you tried 568B ?

        As I said, all premade CAT5e patch cables you buy at a store are 568B. They are not 568A. If you make a home run 568A from a wall jack to the patch panel and use a 568B patch cable [premade bought from a store or dealer] you just created a cross over cable. I’ve seen it happen where the data cable guys cable the office 568A and the IT guys use premade patch cables and then scratch their heads on why it doesn’t work. The contractor says they tested all runs ok, so not their fault, but failed to say they wired the entire office 568A so all those 568B patch cables the IT guys bought won’t work.

      • #2810441

        Reponse To Answer

        by the dobc ·

        In reply to have you tried 568B ?

        Who is the idiot that keeps saying that one run punched 568A and a patch cable wired 568B will make a crossover? I think you need to re-read the books!

      • #2809881

        Reponse To Answer

        by cg it ·

        In reply to have you tried 568B ?

        I am…

        a cross over is:
        568A hook under/ right to left: brn/brnwht/org/bluwht/blu/orgwht/grn/grnwht on one side.

        568B hook under/ right to left: brn/brnwht/grn/bluwht/blu/grnwht/org/orgwht.

        you wire up the office 568A and buy your standard patch cable from the store and use it which is 568B wiring…what do you get?

        that’s a cross over cable:

      • #2809857

        Reponse To Answer

        by brucemc123 ·

        In reply to have you tried 568B ?

        You’re right… a crossover cable is 568A on one end and 568B on the other end. And a straight-through cable has the same wiring scheme on both ends so that all pin numbers are connected to the same pins on the other side (pin 1 to pin one, pin 2 to pin 2, etc.).

        Computers transmit on the pair connected to pins 1 & 2 and receive on the pair connected to pins 3 & 6. Because of this, hubs and switches need to be wired to receive on the pin 1 & 2 pair and transmit on the 3 & 6 pair. But if you want to connect 2 computers directly to each other with one cable you need a crossover cable (568A on one end and 568B on the other) so both computers won’t be trying to transmit on Pins 1 & 2 and receive on pins 3 & 6. The crossover cable connects the transmitting pair on one end to the receiving pair on the other end.

        Most patch cables are 568B but I’ve seen 568A used (on both ends) and it works the same because as long as both ends are the same it’s wired straight-through. And if you connect 2 straight-through cables (even if one is 568A straight-through and the other is 568B straight-through) you still send the signals straight through because what goes in on a particular pin number still comes out on the same pin number at the other end.

        When in doubt… check Wikipedia. 🙂

        http://en.wikipedia.org/wiki/Ethernet_crossover_cable

    • #2810539

      duplicate post

      by cg it ·

      In reply to Simple CAT5 data run just will not work?

      .

    • #2810506

      Does another computer work on same cable?

      by greg.goss ·

      In reply to Simple CAT5 data run just will not work?

      Does another computer work on the cable?
      If not, verify a computer works plugged in at the very beginning of the run.
      Keep moving back down the cable run (plugging in at each connection/junction point) until it no longer connects.

      Are there florescent lights along the run? Motors? fans?

    • #2810488

      Try A Crossover Cable

      by brucemc123 ·

      In reply to Simple CAT5 data run just will not work?

      Are you connecting two devices that need a crossover connection? Most modern hubs and switches are auto-sensing (automatic MDI/MDI-X configuration) but some have a special “uplink” port or even a manual switch when crossover is necessary and some have no crossover capability at all so a crossover cable is required. It’s an easy thing to try just in case. A good explanation can be found on Wikipedia at:
      http://en.wikipedia.org/wiki/Ethernet_crossover_cable

      • #2810450

        Reponse To Answer

        by robo_dev ·

        In reply to Try A Crossover Cable

        Thanks, At the far-end I’ve tried it with both the NIC itself and a switch that does auto-crossover. Since I get link on both ends and my cable tester says my pairing is correct, I think it’s just a bad punchdown, damaged cable, or interference.

    • #2810462

      NIC speed

      by robert.a.hatcher ·

      In reply to Simple CAT5 data run just will not work?

      What type of NIC are you connecting to? I have seen some 1Gbit NICs not work while they attempt to establish layer 1 (physical) across a medium not spec-ed correctly. Have you tried fixing the NIC’s adapter setting to not go to 1 Gbit. If it works at 100 Mbit and shows no CRC errors over some period of large packet pings then your good. Obviously if you want to return to 1 Gbit then you should run a minimum of CAT-5E with CAT-6 preferred.

      • #2810449

        Reponse To Answer

        by robo_dev ·

        In reply to NIC speed

        This is just a 10/100 NIC running at 100.

        Thanks again, everybody, for the input. I promise I will post the results to this mystery once I get back to that site. 🙂

    • #2810412

      Just a thought

      by stlawrence1337 ·

      In reply to Simple CAT5 data run just will not work?

      Does the PC have more than one NIC? I had this happen to a 150ft run during an on-site visit to an aparment complex from their main office to the business center. In the end, everything worked I just had the ethernet plugged into the wrong NIC.

      • #2810403

        Reponse To Answer

        by robo_dev ·

        In reply to Just a thought

        Nope, just one. Good thought though.

    • #2810388

      More ideas to check…

      by alexdatsko ·

      In reply to Simple CAT5 data run just will not work?

      What is their dhcp range set to on the router? if the cable passes the physical test its most likely going to be a router configuration issue for connectivity… if you’re not getting an ip from dhcp, check your default gateway, & subnet mask once again.. You said its a 192.168.0.x network? Make sure you didn’t miss a .1 for the 3rd octet if your mask is 255.255.255.0.. If everything is set up correctly it sounds like a problem with the NIC on the PC, or port on the switch/router on the other side. Try other devices on the drop. Just wondering, why are you terminating to 568A (double check its A on both sides)? In practice, anything works that’s terminated the same on both ends to make it straight-through (don’t listen to the guy saying a 568B both sides patch cable and 568A both sides drop makes a crossover, I’m sure you know better), but 568B is the industry standard for data anymore isn’t it? Not that it matters, I just try to stay consistent because I’ve seen problems with people reterminating drops (without looking at the current setup I guess) not knowing the facilities standard is punched down 568A.

      The only other thoughts I have are possible EMI or RFI being too close to some electrical mains or strong lights, a serious RF transmitter/microwave or something of that nature, or something around 350mhz such as a strongly transmitting wireless KB/mouse/etc.. Also, you might want to check that your router/switch power adapter is putting out the appropriate voltages because spooky tricks can happen when these are failing (or can possibly fry something). Hopefully there was nothing Power injected and plugged into the switch because that can kill a port (although you shouldn’t get a link light after this occurs). Another simple thing to try for L3 over the drop is to take switches & routers out of the mix and put a PC on both sides of the drop and a crossover cable on one side, and set static ip’s on both and make sure you can ping each other. If this is possible it’s definitely the other hardware. Another thought (haha): have you made sure that its not the 192.168.0 subnet that is causing the problem? Some devices will absolutely not use 192.168.0.x, a LAN addy must be 192.168.1.x, (I think some dsl modems/routers at least, have seen this at least once in the field connecting i think a samsung ubigate or possibly a motorola dsl modem to a Cisco 1841).. Have you also made sure the machine is free of virii/trojans? This can obviously impede network connectivity in some cases, but it won’t change when connected directly to the switch vs over the drop.. This sounds more like a NIC issue if the extra impedance (75′ is not enough usually, around 320′ is the normal spec) might be dropping the signal to an amplitude thats too low for the switch/router to ‘hear’. Let us know what you find with this! Have successfully completed plenty of L2 field troubleshoots and it almost never requires new cable, its usually either re-terminate, check IDF/cross connects, or there are device, power, or configuration issues.

    • #2810359

      Simple CAT5 data run just will not work?

      by hsishikawa ·

      In reply to Simple CAT5 data run just will not work?

      Have you checked the cable to make sure the pairs were punched down correctly? I mixed the return of two pairs on both ends once, passed diags but the crosstalk killed the line. Drove me crazy until I found that I screwed up.

    • #2809959

      CAT5 bulk resistance

      by onthefence ·

      In reply to Simple CAT5 data run just will not work?

      I have had problems with “CAT5” that has nearly 3 times the specified bulk resistance (rather than the characteristic impedence). It’s also more prone to breaking. My contractors have been made aware of this and test a sample of the 305m reels when they buy them. I’d be quite surprised if this affected a 75ft run but it’s worth pointing out generally anyway. The supplier was informed that it was out of spec. Should be <60ohms for a 300m loop (twist one end together and measure the two wires at the other end). My installations aren't ethernet.

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