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100BASET question 1

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bithead9

MIS
Jan 27, 2003
183
US
OK - I've been searching and asking questions on cabling and 100 BaseTX. I get two answers. 1) says that all the 8 wires are USED for 100 baset ethernet. UTP. 2) Says only 4 wires are used. Does someone here REALLY know for sure ? If I use a 3COM Office connect HUB will it use 8 wire or 4 ? How about a Cicso Catalyst 2820 device ? I have an etherner run taht is greater then 100Meters (not by alot) currently runs 10baset no problem. Minimal packet loss. Ping times are subsecond and usuall under 10ms. Can I use 100Baset in ANY way ? Is a repeater any better than a hub to extend the signal strength? Are there "industrial" strength devices that work better for the fringe 100M workability ? The existing cable is CAT3. My attempts at using 100baset hubs have the hub go partitioned. No connectivity. If I drop a hub in the middle will that help? Rerunning the cable (right now) is not an option. Any thoughts ?
 
Ethernet uses 2 pairs, orange and green, pins 1/2 & 3/6

FYI,
T-1 uses 2 pairs, pins 1/2 & 4/5 (except 4-wire 56k)
T-1 4-wire 56k uses pins 1/2 & 7/8
Token Ring uses pins 1/2 & 7/8 if I remember correctly

MCSE CCNA CCDA
 
thanks for the prompt reply. hopefully someone here will know about the repeater/hub aspect. some specs I saw online were for 100base t4 (it uses all 8 wires).
 
100BaseT
100 – 100 Megabit per second transmission rate
Base – Baseband transmission versus Broadband (cable, roadrunner, etc)
T – Twisted pair versus coax

100BASE-TX only require two pairs to operate, pins 1 and 2 (transmit or TX), and pins 3 and 6 (receive or RX). CAT5 cable is required minimum. CAT3 will only work at 10 mbps.

A straight-through cable is usually used to connect a node to its network device. In order for two network devices or two nodes to communicate with each other (such as a switch to another switch or computer to computer) a crossover cable is often required at speeds of 10 or 100 Mbit/s.

-3COM Office connect HUB will it use 8 wire or 4 ? 2 pair (4 wires will work)
-Is a repeater any better than a hub to extend the signal strength? A repeater/hub/switch all will work to extend the range. Place the item midrange.
-Are there "industrial" strength devices that work better for the fringe 100M workability ? Don’t go beyond the 100 meter range (80 meter – horizontal seems the best…see previous posts on cable speeds. I have used CAT7 cable for extremely long cables just to get connectivity. The customer did not care if it met the standard or past the tests.
-(existing cable is CAT3) Rerunning the cable (right now) is not an option.

If you use the CAT3 cable and hook up connectors & hubs that are CAT5e rated, you will still only get 10 mbps speed.


Regards
Peter Buitenhek
ProfitDeveloper.com

"Never settle for a job well done...always look for cost cutting measures
 
THANK you very much for the blow by blow answers! This is exactly what I was trying to get. I am going to have to figure a way to rerun the CAt3. Its the only way. And if I do that its gonna be fiber.
 
bithead9:

I think your confusion stems from the fact that there was/is an early 100BaseT4 standard that did use all 4 pairs, if any current equipment supports it is anybody's guess.
 
YES! Exactly. I found 100base t4 and tx and net the mfg says 100base - there are even more spec that "never caught on".
That extender module looks neat. I will have to get a quote. 50Mbit is not bad. Still 5 times faster than what is in place now.

Thanks for all your reponses!
 
Blackbox makes the same type of extender... just used one to extend the dmark for a T1

------------------------------------
Dallas, Texas
Telecommunications Tech
CCVP, CCNA, Net+

CCNP in the works
 
At $676 for the pair its a tough call. I could run fiber and get media converters for about the same (prob lees) $.
Of course the old cable can be used and save lots of time...hmmm.

How about I double the pairs of cat3? for the 4 wires I join two together. that effectively doubles the cable "size" and mass. Will that help get 100BaseT to work or is the CAT3 a lost cause? Anyone ever tried this ?
 
Running fiber is the best choice.

But based on your initial post I assumed this was "not an option".

Doubling the pairs has no affect on the ethernet distance limitations.

MCSE CCNA CCDA
 
bithead9 - you wrote: How about I double the pairs of cat3? for the 4 wires I join two together. that effectively doubles the cable "size" and mass.

The data speed of the cable can be equated to:
1. a rural dirt road - CAT3
2. a suburban street - CAT5e
3. a superhighway - CAT6 (CAT6e, CAT7, fiber)

The data encryption & physical properties of the cable (road) limit the electrical speed. By increasing the number of lanes on the dirt road (joining CAT3 cables together), you cannot reach superhighway speeds. You can go slower on a superhighway but you risk the chance of a costly rear end collision (over paying for a high speed cable when you only need slow or medium speed..sic).

Regards
Peter Buitenhek
ProfitDeveloper.com

"Never settle for a job well done...always look for cost cutting measures
 
Peter, how does that work? Cat5e runs gigabit just fine, and Cat 6 doesn't run 10 Gig as far as I know.

Also curious what data encryption has to do with the speed of electricity?
 
Cat 5, Cat 5e, Cat 6, and Cat 6a all run gigabit to 100 meters.

Cat 6 does 10 gigabit, 55 meters max.

Cat 6a does 10 gigbit to 100 meters.



I tried to remain child-like, all I acheived was childish.
 
Doubling the pairs may actually decrease the maximum length of your cable since the number of twists per inch in each pair is engineered to minimize electrical interference to adjoining pairs.

Using Cat 3 with 100 MBit devices may not limit the throughput to 10 MBit. Each situation is different and what does not work in one may very will work in another. I have installed Cat6 to join two 1GB switches at 460' distance because the customer had no affordable options and it has been working flawlessly for several years. I have installed 125' runs that picked up so much noise that I had to replace with shielded or fiber, even though the original installation was by the book.
 
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