Can a regular fast Ethernet switch use CAT3 wiring instead of CAT5 wiring to transmit 100Mbps over short distances? CAT3 is usually used in telephone networks, and I know it can support 10Base-T at 10Mbps. 100Base-T aka Fast Ethernet is supposed to have CAT5 at minimum. What happens if CAT3 is used? I know it is not recommended, but will it work, or will the switch auto fall back to 10Mbps?
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100Mbps Using CAT3 on short distances? 3
- Thread starter ispwiz
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tnphoneman
Vendor
I started working for a LEC in 1998 and our office had Cat3 wiring terminating in 66 blocks and the other end of the cable had 2 RJ45 jacks. This way we got 2 network drops for each cable. At the time we had old 10 meg switches and it worked fine.
In 2007 we upgraded to 100 MB switches. Guess what it still works fine. Our longest run was 200' in a drop ceiling and over flourescent light fixtures, conduits, etc. It is a myth that you have to use Cat5 for it to work. That is as long as you do not have RF or EMF interference causing inductance into your cable.
Here is what I would do. Are these homeowners or rentals? I would install this as is and tell them that if there are problems then you would need the access to pull new cable and they would probably agree. You would probably have to work some odd hours to accomodate the owner.
2nd is that if you have to pull cable, the best thing is to run a conduit to each so the next time you have to pull a cable you only need access to both ends.
If this is a condo unit then there has to be some sort of access to all attics. What if the end unit needed some new electrical service run? What about under the buildings? Is there a crawl space?
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In 2007 we upgraded to 100 MB switches. Guess what it still works fine. Our longest run was 200' in a drop ceiling and over flourescent light fixtures, conduits, etc. It is a myth that you have to use Cat5 for it to work. That is as long as you do not have RF or EMF interference causing inductance into your cable.
Here is what I would do. Are these homeowners or rentals? I would install this as is and tell them that if there are problems then you would need the access to pull new cable and they would probably agree. You would probably have to work some odd hours to accomodate the owner.
2nd is that if you have to pull cable, the best thing is to run a conduit to each so the next time you have to pull a cable you only need access to both ends.
If this is a condo unit then there has to be some sort of access to all attics. What if the end unit needed some new electrical service run? What about under the buildings? Is there a crawl space?
Signature===========================================
Artificial Intelligence Is No Match for Natural Stupidity.
The latest survey shows that 3 out of 4 people make up 75% of the population.
The original point and click interface was a Smith & Wesson.
Red meat is not bad for you, it is the green fuzzy meat that is bad.
I would not use "Cat 3". There is no substitute for peace of mind! "Cross-talk" is going to be a issue which affects performance,If you use "cat 3" at 100 mb or higher.Can you look a client in the eye and guarantee that person that they have have at least the minimal performance?I think not. what legal ramifications does skimping on wire have? Do you value your rep? How much are you going to save in the long run by using cat3? Prices are going up so 5 years from now when you have to do it again you will actually pay more. go ahead and bite the bullet and put in the best you can afford now or stay at 10mb and be happy.
people who say you can run it haven't had any formal training on network cabling please be cautious. get someone in with a good cable analyzer to test cat 3 at cat5 and above levels and see what happens.
people who say you can run it haven't had any formal training on network cabling please be cautious. get someone in with a good cable analyzer to test cat 3 at cat5 and above levels and see what happens.
dagwoodsystems
Programmer
There once existed something called 100BASE-T4. As suggested by the name, four twisted pairs (all eight wires) were used to produce a "fast ethernet" link over CAT3. I doubt any of the new switches support this old method of Ethernet signalling/negotiation, which involved the use of QAM. I'm sure that new NICs don't either. I mean, you'd have to find some old ISA bus stuff that no one makes or supports anymore.
Anyway, my point is that you weren't dreaming when you thought you once heard that CAT3 would support a 100Mbps Fast Ethernet connection. But it was never made a standard; instead CAT3 was demoted to support 16Mbps at 100Mhz.
While it may appear that you "pulled it off" by getting a 100M link light on your switch, I would expect a quality tester to show a great deal of errors. You won't see the errors directly at the Application layer. Instead, it will manifest itself as random slowness and excessive chatter at the switch.
Replace all horizontal wiring with 5e or better. It's the standard.
Tim Alberstein
Anyway, my point is that you weren't dreaming when you thought you once heard that CAT3 would support a 100Mbps Fast Ethernet connection. But it was never made a standard; instead CAT3 was demoted to support 16Mbps at 100Mhz.
While it may appear that you "pulled it off" by getting a 100M link light on your switch, I would expect a quality tester to show a great deal of errors. You won't see the errors directly at the Application layer. Instead, it will manifest itself as random slowness and excessive chatter at the switch.
Replace all horizontal wiring with 5e or better. It's the standard.
Tim Alberstein
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