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Conference netcad::hub_mgnt

Title:DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:NETCAD::COLELLADT
Created:Wed Nov 13 1991
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:4455
Total number of notes:16761

2397.0. "Crossover cables and NPG products" by DPDMAI::DAVIES (Mark, SCA Area Network Consultant) Tue Jun 20 1995 08:47

    Is there a comprehensive list of the UTP cable crossover requirements
    for NPGs networking products?  I am working a configuration which
    includes GIGAswitch/FDDIs, DECswitch 900EFs, PEswitch 900TXs and
    PORTswitch 900TPs and have found that all the UTP cables cannot be the
    same, ie, some require a crossover and some do not.
    
    A list of the UTP products we make and whether or not they include an
    internal crossover would be very useful.  If one exists, a pointer
    would be appreciated.
    
    What I have found for ports using UTP, assuming that the device
    connecting to the UTP port has no internal crossover, are as follows:
    
    	GIGAswitch/FDDI	 - normal crossover cable                      
    	DECswitch 900EF	 - normal crossover cable
    	PEswitch 900TX	 - straight through cable (internal crossover)
    	PORTswitch 900TP - straight through cable (internal crossover)
    
    Can someone confirm these are correct?
    
    Thanks,
    
    Mark
T.RTitleUserPersonal
Name		DateLines
2397.1A little more infoDPDMAI::DAVIESMark, SCA Area Network ConsultantTue Jun 20 1995 10:4618
    I have found out that by 802.3 rules, all repeaters must have an
    internal crossover.  
    
    The PEswitch 900TX also has an internal crossover because it can be
    used to replace a repeater, eg, a desktop bridge.
    
    The DECswitch 900EF is a backbone bridge and does not have an internal
    crossover.
    
    FDDI connections by default do not have an internal crossover.
    
    Any comments are welcome.
    
    Regards,
    
    Mark
2397.2To crossover or not to crossover....NETCAD::BATTERSBYTue Jun 20 1995 11:0820
    >What I have found for ports using UTP, assuming that the device
    >connecting to the UTP port has no internal crossover, are as follows:
         
    >GIGAswitch/FDDI  - normal crossover cable
    >DECswitch 900EF  - normal crossover cable
    >PEswitch 900TX   - straight through cable (internal crossover)
    >PORTswitch 900TP - straight through cable (internal crossover)
        
    Yup, I believe that you've got it right (the only one I'm not too familiar
    with is the GIGAswitch/FDDI using copper PMDs).
    Bridges/switches (departmental) typically have no internal crossover.
    (exception is the PEswitch (desktop switch) which has internal crossover.
    Repeaters (10Base-T) typically always have internal crossover.
    Mau's I believe typically don't have internal crossover.
    Bottom line is know what device is being connected at each end and 
    use the appropriate TP cable.
    
    Bob
    PS: You may want to inquire about copper FDDI crossover/no crossover
    in the FDDI notes conference, to be sure there.
2397.3One to watch forKERNEL::MCSKEANEPone bit brain with parity errorWed Jun 21 1995 09:553
    
    The DECrepeater350 DETPR-AB (UK Part No.) does not have an internal
    crossover on its twisted pair ports.