Conference 7.286::fddi

1242.0. "TP-PMD Standard Update" by LEVERS::B_CRONIN () Mon Feb 21 1994 09:34

    The TP-PMD standard was forwarded to public review at last week's FDDI
    standards meeting. If past experience is a guide, we are now done with
    the technical work on the document. While it is procedurally possible
    for changes to be made, this usually does not happen, since most people
    who are technically involved have already commented on the work. 
    
    The document revision will be changed from 2.0 to Rev 2.1 for the public 
    review version. The new document will become available in about 6-8 weeks. 
    The public review period lasts 120 days, beginning when ANSI publishes 
    the Rev 2.1 draft. They will give it an X3.abc type of number. I'll post 
    the number here when I know what it is. 
    
    Keep tuned for product plans around products that will comply with the
    final version of the standard. There is no reason to believe that the
    current products will not be interoperable with the fully compliant
    versions, when they become available. 
    
    FYI, FDDI business will now be handled by X3T12, which is a new technical 
    committee formed because of the disbanding of X3T9. The FDDI committee 
    X3T9.5 was formerly a Task Group of Technical Committee X3T9; it is now a
    Technical Committee in its own right. So, if you see mention of X3T12,
    its the same bunch as X3T9.5, but, they have a new name. 
    
    Finally, if you are following the FAST Ethernet craze, this is the
    same PMD that will be used by the 100BASE-X version of 100 Mbit
    CSMA/CD. 

Hi,

I think we need to know the guidelines for designing the correct cabling and 
to do so, we need to understand why the only 4 connectors at most on a link are
supported for Cat 5 UTP.

Could anyone tell me why only 4 connectors?

Kenji

    The 4 connectors were chosen because the addition of connectors
    causes additional crosstalk, which degrades the signal to crosstalk 
    ratio. The number 4 limits the degradation to about 2 dB.