What kind of ethernet-looking cable is this?
September 2, 2011 5:13 AM Subscribe
What kind of ethernet-looking cable is this?
In my office there are some RJ45 jacks on the walls (I think there are three double jacks in various parts of the office) and at one point on the wall near the entrance, there are 7 cables that look like cat5 cable coming out of the wall with unconnected ends, presumably related to the jacks. For years I've assumed that it was all ethernet cable and had it as a back-burner project to connect it to a patch panel or switch and have in-wall ethernet for a LAN. Today I got around to it and stripped one of the cables at the wall where the 7 raw cables are all coming out, and discovered that it is probably not cat5. But, it also doesn't appear to be the color scheme for ISDN so I'm unclear on what I'm looking at.
Basically, there is the usual gray sheath, and then the usual foil shielding, and inside there are the usual 8 wires. However, they are not twisted into pairs, and the color scheme of the wires is:
green
red
brown
blue
yellow
white
white
white
The three white cables are absolutely positively not white + other color, they are entirely white. What are these cables supposed to interconnect? Bonus: is there any way I can pervert them to my ethernet-requiring purposes or is it a lost cause (or are they likely carrying voltage and are both a lost cause and a router-killing risk)? I'm in Germany in case it matters. Thanks for any info!
In my office there are some RJ45 jacks on the walls (I think there are three double jacks in various parts of the office) and at one point on the wall near the entrance, there are 7 cables that look like cat5 cable coming out of the wall with unconnected ends, presumably related to the jacks. For years I've assumed that it was all ethernet cable and had it as a back-burner project to connect it to a patch panel or switch and have in-wall ethernet for a LAN. Today I got around to it and stripped one of the cables at the wall where the 7 raw cables are all coming out, and discovered that it is probably not cat5. But, it also doesn't appear to be the color scheme for ISDN so I'm unclear on what I'm looking at.
Basically, there is the usual gray sheath, and then the usual foil shielding, and inside there are the usual 8 wires. However, they are not twisted into pairs, and the color scheme of the wires is:
green
red
brown
blue
yellow
white
white
white
The three white cables are absolutely positively not white + other color, they are entirely white. What are these cables supposed to interconnect? Bonus: is there any way I can pervert them to my ethernet-requiring purposes or is it a lost cause (or are they likely carrying voltage and are both a lost cause and a router-killing risk)? I'm in Germany in case it matters. Thanks for any info!
Response by poster: I'm not sure what these cables are, but, if the wires are not twisted into pairs then they're not going to work for ethernet over any significant distance.
Yeah, that was my expectation but I figured I it didn't hurt to ask. My main goal here is to beat the bandwidth of my 802.11g wireless but it seems pretty unlikely that these cables will have any use as far as that goes. What's annoying is that they don't seem to have been run through any kind of duct but instead were fully plastered into the wall, so there's also no option of using the existing run to run new cable through. I'm still interested in finding out what they are if anyone knows.
posted by Your Time Machine Sucks at 5:47 AM on September 2, 2011
Yeah, that was my expectation but I figured I it didn't hurt to ask. My main goal here is to beat the bandwidth of my 802.11g wireless but it seems pretty unlikely that these cables will have any use as far as that goes. What's annoying is that they don't seem to have been run through any kind of duct but instead were fully plastered into the wall, so there's also no option of using the existing run to run new cable through. I'm still interested in finding out what they are if anyone knows.
posted by Your Time Machine Sucks at 5:47 AM on September 2, 2011
Response by poster: As mentioned, the other ends presumably terminate in the three double RJ45 jacks that are dispersed throughout this physically-small office. At some point, there was probably some kind of routing device attached to the wall where this bunch of now-unterminated cables all emerge from the wall together.
posted by Your Time Machine Sucks at 6:05 AM on September 2, 2011
posted by Your Time Machine Sucks at 6:05 AM on September 2, 2011
Response by poster: Just to clarify, I'm not confused about how I would network 7 unterminated ethernet cables coming out of a wall that went out to ethernet jacks distributed throughout the office. I'm just confused about what these cables are, and whether there is any hope of doing normal networking things with them (sounds like they would have too much signal loss to be usable, so now I'm just trying to figure out what they are so I know how best to pack them away instead of having them sticking out of the wall).
posted by Your Time Machine Sucks at 6:14 AM on September 2, 2011
posted by Your Time Machine Sucks at 6:14 AM on September 2, 2011
can you see if the whites match up to a particular color, or the yellow to the brown in the rj45 jack?
posted by fozzie33 at 6:17 AM on September 2, 2011
posted by fozzie33 at 6:17 AM on September 2, 2011
Best answer: it sounds like a cheap cat5 cable... i'd imagine the whites do match up to a color, i'd check a jack to see if they are labeled there... i've had to deal with times when cat 5 cables had no stripes, took some time,but was able to make them work, with the help of a cable tester.
posted by fozzie33 at 6:21 AM on September 2, 2011
posted by fozzie33 at 6:21 AM on September 2, 2011
Response by poster: Is there such a thing as cat5 so cheap that it has no twisted pairs?
posted by Your Time Machine Sucks at 6:24 AM on September 2, 2011
posted by Your Time Machine Sucks at 6:24 AM on September 2, 2011
could be a low voltage cable sold as a cat 5, it'd still work, but you'd probably have some issues with it... still doing some research though...
posted by fozzie33 at 6:24 AM on September 2, 2011
posted by fozzie33 at 6:24 AM on September 2, 2011
I'm pretty sure if it ain't twisted pairs it ain't CAT5.
posted by BigLankyBastard at 6:27 AM on September 2, 2011
posted by BigLankyBastard at 6:27 AM on September 2, 2011
I'm pretty sure if it ain't twisted pairs it ain't CAT5.
Right. Fairly tightly twisted pairs are essential to meet the category 5 specs. If the twist isn't readily apparent, then it's some kind of low-bandwidth cable, like maybe telephone cable or for low-speed data. Like serial port speed for a text terminal sort of thing.
Even telephone cable is usually a form of twisted pair, just the twist is very long, so it's hard to notice it sometimes. The general rule is that the higher the bandwidth, the more tightly twisted the pairs must be.
Does this cable have anything printed on the outside of the jacket?
posted by FishBike at 6:35 AM on September 2, 2011
Right. Fairly tightly twisted pairs are essential to meet the category 5 specs. If the twist isn't readily apparent, then it's some kind of low-bandwidth cable, like maybe telephone cable or for low-speed data. Like serial port speed for a text terminal sort of thing.
Even telephone cable is usually a form of twisted pair, just the twist is very long, so it's hard to notice it sometimes. The general rule is that the higher the bandwidth, the more tightly twisted the pairs must be.
Does this cable have anything printed on the outside of the jacket?
posted by FishBike at 6:35 AM on September 2, 2011
Response by poster: Does this cable have anything printed on the outside of the jacket?
Nothing that can be seen on the cable where it emerges from the wall.
posted by Your Time Machine Sucks at 6:43 AM on September 2, 2011
Nothing that can be seen on the cable where it emerges from the wall.
posted by Your Time Machine Sucks at 6:43 AM on September 2, 2011
It might be cat3 cable. The apartment I used to live in was wired with cheap cat3, and if it was twisted, it was barely twisted. I ran some Cat5e to save headaches.
posted by rockindata at 6:44 AM on September 2, 2011
posted by rockindata at 6:44 AM on September 2, 2011
Response by poster: I'm responsible for the cabling.
posted by Your Time Machine Sucks at 7:52 AM on September 2, 2011
posted by Your Time Machine Sucks at 7:52 AM on September 2, 2011
Response by poster: And I have a non-cheap multimeter.
posted by Your Time Machine Sucks at 7:54 AM on September 2, 2011
posted by Your Time Machine Sucks at 7:54 AM on September 2, 2011
It's possible you're looking at old phone/intercom cabling, that all terminated in a main panel/switcher/cal box for a receptionist - in that case, it might be something oddly proprietary and the only thing would be to test out (like everyone says) and see what you get. I was once in an old office that was riddled with something similar, from the pre-VOIP/centrally located PBX days...
posted by pupdog at 8:08 AM on September 2, 2011
posted by pupdog at 8:08 AM on September 2, 2011
I'm in Germany in case it matters.
This wiring scheme doesn't even match the old German RJ-11 color set:
Violet
Green
White
Brown
Yellow
Slate
On preview: I'm with pupdog, it looks proprietary. I'd replace with cat5e or cat6 and call it a day.
posted by Mister Fabulous at 8:12 AM on September 2, 2011
This wiring scheme doesn't even match the old German RJ-11 color set:
Violet
Green
White
Brown
Yellow
Slate
On preview: I'm with pupdog, it looks proprietary. I'd replace with cat5e or cat6 and call it a day.
posted by Mister Fabulous at 8:12 AM on September 2, 2011
for running cable, could you pull from rj45 the current cable? if so, could you pull through new cat5e cables (splice them to current cable, then pull through?
posted by fozzie33 at 8:17 AM on September 2, 2011
posted by fozzie33 at 8:17 AM on September 2, 2011
Response by poster: What's annoying is that they don't seem to have been run through any kind of duct but instead were fully plastered into the wall, so there's also no option of using the existing run to run new cable through.
posted by Your Time Machine Sucks at 8:45 AM on September 2, 2011
posted by Your Time Machine Sucks at 8:45 AM on September 2, 2011
I have found old, proprietary office telephone connectors that looks like an RJ45 jack, but with an extra little flange at one corner. Could it be that?
posted by wenestvedt at 9:02 AM on September 2, 2011
posted by wenestvedt at 9:02 AM on September 2, 2011
If someone pulled the cables poorly, and applied a lot of tension to them, they could have untwisted significantly. Not seeing twists in the last foot or so of cable is a bad sign, but doesn't necessarily indicate that the cable wasn't originally some type of twisted pair.
I can't say exactly what those cables are to, but I tend to think multiline phone system. There were a lot of competing proprietary multi-line phone systems in the 70s-90s, some analog and some digital and some weird hybrids. It's not impossible that you could have something like two voice pairs and then a couple of untwisted wires for (say) switching lines or something.
Does the cable sheath not say anything at all? If you tug on it and can get a bit more out of the wall, maybe there's some sort of maker's mark printed on it. Absent that, it may be very hard to tell for sure.
posted by Kadin2048 at 9:33 AM on September 2, 2011
I can't say exactly what those cables are to, but I tend to think multiline phone system. There were a lot of competing proprietary multi-line phone systems in the 70s-90s, some analog and some digital and some weird hybrids. It's not impossible that you could have something like two voice pairs and then a couple of untwisted wires for (say) switching lines or something.
Does the cable sheath not say anything at all? If you tug on it and can get a bit more out of the wall, maybe there's some sort of maker's mark printed on it. Absent that, it may be very hard to tell for sure.
posted by Kadin2048 at 9:33 AM on September 2, 2011
Oh, and even if you can't use the existing cable, it might be possible to use them to pull a new run of Cat5e or Cat6 through the walls, particularly if you can get up into the plenum to help it around any hard bends or corners. Better than nothing, anyway, assuming it's not stapled to the studs.
posted by Kadin2048 at 9:35 AM on September 2, 2011
posted by Kadin2048 at 9:35 AM on September 2, 2011
Response by poster: The walls aren't drywall, they are plastered, and the cables are embedded in the plaster for some stupid reason. In order to use the current location of these cables as the future location of other cables, a sledgehammer would need to be employed.
posted by Your Time Machine Sucks at 9:56 AM on September 2, 2011
posted by Your Time Machine Sucks at 9:56 AM on September 2, 2011
How old are they ? if its from the 90's could it be token ring?
posted by majortom1981 at 10:25 AM on September 2, 2011
posted by majortom1981 at 10:25 AM on September 2, 2011
Response by poster: They could be from the 90s.
posted by Your Time Machine Sucks at 10:31 AM on September 2, 2011
posted by Your Time Machine Sucks at 10:31 AM on September 2, 2011
IT could have been for phones. From what I understand most phone systems do not care about being twisted or not or what color as long as its the same at either end.
Sounds like it was just cheap shielded ethernet cable used to connect phones.
posted by majortom1981 at 10:38 AM on September 2, 2011
Sounds like it was just cheap shielded ethernet cable used to connect phones.
posted by majortom1981 at 10:38 AM on September 2, 2011
I also think it's probably cat3 or just voice-grade cable, whose twist if any was loose enough that it's not visible from outside the wall (combining rockindata's and odinsream's suggestions). That is what you would find going to an old multiline handset of the sort that might have been installed from the '60s(?) through the '90s.
The fact that it's shielded argues against it being "cheap ethernet cable"— ethernet doesn't need to be shielded, they wouldn't go to that expense if they were just cutting corners.
My guess is that you could probably run 10Mbps ethernet over a short distance of this and may be able to run 100Mbps ethernet, though the cable is out of spec for either.
Alternately, there are all sorts of short-haul modems (oftentimes similar to DSL modems) that you can use to get a higher bit rate across untwisted, voice-grade wiring.
posted by hattifattener at 2:30 PM on September 2, 2011
The fact that it's shielded argues against it being "cheap ethernet cable"— ethernet doesn't need to be shielded, they wouldn't go to that expense if they were just cutting corners.
My guess is that you could probably run 10Mbps ethernet over a short distance of this and may be able to run 100Mbps ethernet, though the cable is out of spec for either.
Alternately, there are all sorts of short-haul modems (oftentimes similar to DSL modems) that you can use to get a higher bit rate across untwisted, voice-grade wiring.
posted by hattifattener at 2:30 PM on September 2, 2011
If it is embedded in plaster, it has been around for a while. My money is on some kind of serial cable that was connected to terminals and a little controller of some kind.
What does the exterior of the cable say? Does it have any markings?
posted by gjc at 4:43 PM on September 2, 2011
What does the exterior of the cable say? Does it have any markings?
posted by gjc at 4:43 PM on September 2, 2011
Response by poster: If it is embedded in plaster, it has been around for a while.
Not in Berlin. It just means that it was put in there when the place was last renovated (could be a decade ago, could be 15 years, but I'm guessing you meant a longer while than that). If I wanted to renovate this office today, I would be calling plasterers.
I'm leaning towards the cat3 theory. I was also interested in this comment in this discussion which shows an almost-identical color scheme. I'm going to start by tracing which cable goes to which jack and see if it's possible to connect them to my patch panel and see what kind of signal loss we're looking at. It only has to beat real-world wireless bandwidth to make it useful for me.
What does the exterior of the cable say? Does it have any markings?
See above.
posted by Your Time Machine Sucks at 2:52 AM on September 3, 2011
Not in Berlin. It just means that it was put in there when the place was last renovated (could be a decade ago, could be 15 years, but I'm guessing you meant a longer while than that). If I wanted to renovate this office today, I would be calling plasterers.
I'm leaning towards the cat3 theory. I was also interested in this comment in this discussion which shows an almost-identical color scheme. I'm going to start by tracing which cable goes to which jack and see if it's possible to connect them to my patch panel and see what kind of signal loss we're looking at. It only has to beat real-world wireless bandwidth to make it useful for me.
What does the exterior of the cable say? Does it have any markings?
See above.
posted by Your Time Machine Sucks at 2:52 AM on September 3, 2011
Response by poster: Update: I unattached one of the RJ45 jacks at the wall and discovered that the same 8 strands were fed into the two separate jacks (4 in one, 4 in the other). I attached a new RJ45 jack with an arbitrary mapping of the weird colors to the normal colors which I noted down (with all 8 strands going into a single jack in the usual fashion) and punched it down, and attached an ethernet cable to the new jack that was long enough that I could drag it to the wall where all 7 unfinished cables emerge.
Then I used my multimeter to test all the cables for continuity against the wires in the connector of the long cable until I found the cable that went to the jack I just installed, and then I attached it to my patch panel with the same arbitary color mapping.
Result: faster-than-my-wireless networking. Pings between machines on the same network are about half of what they were with the wireless, and I guess I'd say that practically speaking there's about twice the bandwidth. There were twisted pairs to be seen at the replacement jack wall, so I think fozzie33 was right that it was cheap cat5 and odinsdream was right that it was cheap cat5 with twisted pairs that were no longer visible at one end at all.
Thanks all! Because of the generally-encouraging tone about the possibility of getting a little bit of bandwidth out of these cables, I decided it was worth the annoyance of giving it a serious try, and as a result I have working in-wall ethernet which is a major improvement to my office.
posted by Your Time Machine Sucks at 10:22 AM on September 5, 2011
Then I used my multimeter to test all the cables for continuity against the wires in the connector of the long cable until I found the cable that went to the jack I just installed, and then I attached it to my patch panel with the same arbitary color mapping.
Result: faster-than-my-wireless networking. Pings between machines on the same network are about half of what they were with the wireless, and I guess I'd say that practically speaking there's about twice the bandwidth. There were twisted pairs to be seen at the replacement jack wall, so I think fozzie33 was right that it was cheap cat5 and odinsdream was right that it was cheap cat5 with twisted pairs that were no longer visible at one end at all.
Thanks all! Because of the generally-encouraging tone about the possibility of getting a little bit of bandwidth out of these cables, I decided it was worth the annoyance of giving it a serious try, and as a result I have working in-wall ethernet which is a major improvement to my office.
posted by Your Time Machine Sucks at 10:22 AM on September 5, 2011
Yeah, my own experience running ethernet over voice-grade (non-cat5) UTP or incorrectly-wired cat5 is that it would simply cut out from time to time; when it was working, it had exactly the same bandwidth and latency as proper cabling. (I don't know if it cut out because of interference, or because random packet loss would occasionally exceed some threshold.)
Nevertheless, if it works, it works.
posted by hattifattener at 12:15 PM on September 5, 2011
Nevertheless, if it works, it works.
posted by hattifattener at 12:15 PM on September 5, 2011
Response by poster: Packet loss is what you should really be looking at.
What's the best way to measure this?
posted by Your Time Machine Sucks at 1:54 PM on September 5, 2011
What's the best way to measure this?
posted by Your Time Machine Sucks at 1:54 PM on September 5, 2011
Response by poster: I just did a ping test of 1000 64B packets sent from a machine on one end of the cable to a machine on the other and had 0% packet loss, so I think probably the best thing to do is use it for a while and see how it works over time. At the moment it looks good enough.
posted by Your Time Machine Sucks at 2:16 PM on September 5, 2011
posted by Your Time Machine Sucks at 2:16 PM on September 5, 2011
Response by poster: I've been using the new LAN for a couple of weeks now and it's extremely reliable. Thanks again all!
posted by Your Time Machine Sucks at 12:16 AM on September 17, 2011
posted by Your Time Machine Sucks at 12:16 AM on September 17, 2011
This thread is closed to new comments.
I'm not sure what these cables are, but, if the wires are not twisted into pairs then they're not going to work for ethernet over any significant distance. You could sometimes get away with a few feet of untwisted patch cable with 10 megabit ethernet, but for modern 100 meg or gigabit ethernet, it just doesn't work.
posted by FishBike at 5:21 AM on September 2, 2011