1000 base-X ethernet over cat 5 cable

[melexia]

Hi all,

have anybody used RJ-45 connector and cat 5 cable for 1000 base-x ethernet communication?
is it like cat 5 cable will not work at 1.25 gb/s?
if anybody has experienced these scenario please reply........


thanks

 

[FoxyRick]

Do you really mean Cat-5, or the more recent Cat-5e? I'm not sure if you can even buy plain Cat-5 now.

(irrelevant further comments deleted - sorry)

 

[mrflibble]

Have used cat-5 for gbit, and that worked just fine. You don't get any "It Will Work [tm]" assurances from the manufacturer however since it's only rated for 100 MBit. But in 2012 why would you want to use cat-5? It used to be that cat-5 was cheaper than cat-5e, but these days cat-5e is so common...

 

[FvM]

You want to create your own 1000BASE-X spec., different from IEEE defined 1000BASE-CX? The latter is specified with 150 ohm differential impedance and 25 m reach. If you want to make a 100 ohm link with any Category 5/6/7 cable, it's mainly a matter of intended length. None of these cable types has defined behaviour at 1250 MBPS, but it will surely work over short distance.

 

[melexia]

thanks for replying mrflibble
its cat5e only, my mistake........
cat5e works for gbit, it is mentioned everywhere that it is used for 1000 base-t ethernet, but my confusion was in 1000 base-t data transfer happens at 1000 Mbits per second and the application where I want to use it is 1000 base-x which will work at 1.25 Gbits per second.

---------- Post added at 05:16 ---------- Previous post was at 05:15 ----------

thanks FvM
u have shared useful information

 

[permute]

I think 1000BASE-X is an alternative to SGMII. The high speed serial lines embed the clocking and low-rate control information by using 8b/10b coding. 8b/10b selects 256 of the 1024 possible 10b values and uses them to transmit 8b of information. This ensure all 10b codewords have at least one bit set. Furthermore, actual applications also allow the inverted version of a codeword. This leads to a system where an equal number of 1's and 0's can be transmitted even when the data doesn't change. There are 512 remaining codewords, and some of these are then used for control characters (serial sync token for example). The data rate is still 1Gbps minus any protocol overhead.

some devices will support 1000BASE-X to 2.5Gbps (3.125 Gbps before 8b/10b). This is to allow ethernet interconnection of chips where a 1000BASE-X switch would be useful.

 

[melexia]

@permute
Yes 1000 base-X is an alternative to SGMII.
While comparing 1000 base-t and 1000 base-x I concluded that in 1000 base-t actual bit rate is 1000 Mbits per second and in 1000 base-x actual bit rate is 1250 Mbits per second (to accommodate 10 bit information). But then this will mean I can not connect 1000 base-x ethernet port directly to a computer port even for testing, I will have to have a switch which will convert 1000 base-x to 1000 base-t so that computer will understand it.
Am I going wrong way? please reply whatever you suggest

thanks

 

[FvM]

I'm not aware of 1000BASE-X copper media interfaces used in a retail product. -X has been mainly implemented as -LX fibre interface. 1GBit ethernet is a synonym for 1000BASE-X with present computer products. It implements 4x250 MBPS with a 125 Mbd symbol rate.

I doubt if there will be a dedicated 1000BASE-X to 1000BASE-T converter. You'll rather connect two PHYs back-to-back through GMII.

P.S.: As in this paper ftp://ftp.t10.org/t11/document.05/05-336v0.pdf

P.P.S.: There's a type above, I meant 1GBit Ethernet is a synonym for 1000BASE-T

 

[melexia]

1000Base-X is surely not used with copper media interfaces generally. -X is further defined as -LX and -SX depending upon the characteristics of fiber used.
I dont think 1Gbit ethernet is a synonym for 1000Base-X because you dont have a fibre/ SFP port to a computer.
I have searched on internet there are 1000Base LX/SX to 1000 Base-T converters available in the market.
The paper you have refered itself says that you can connect 1000 Base-x and 1000 Base-t via GMII interface. this sentence says that u need a converter for the same.
thanks for the paper.

 

[FvM]

You are right, I actually meant that all recent 1GBit copper implementations are 1000BASE-T.

you can connect 1000 Base-x and 1000 Base-t via GMII interface. this sentence says that u need a converter for the same.

In fact both sides need a converter which is represented by the respective PHY. An elastic buffer may be required for the back-to-back connection in addition.