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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

2241.0. "Concentrator 900MX Problem - need solution fast !" by MARIN::JONES () Mon May 01 1995 23:39

    Hi,
    
    Can anyone help on this one. We have a DEChub900 Multiswitch, to which
    we have DEConcentrator 900MX connected (slot 7). We have configured
    it so that the A/B Channels point inward onto an internal FDDI Ring
    we have created. Upon powering up the unit, all self tests complete
    ok (LED's all green on top of unit). When we go to connect one of
    our Alpha systems which has a DEFTA-UA card in them.. the LED's
    on this unit continually flash green instead of going off as I believe
    they should do. We are using Twisted Pair cable with MJ connectors, 
    cable spec is Cat 5. Consequently when we try and ping this system,
    we are getting now response even though we've re-configured it to
    use fta0 with netsetup (OSF/1 V3.0)
    
    
    
    
    What can I do here to try and troubleshoot the problem more... ? ..
    indeed how can I fix this problem...
    
    Thanks
    
    	/Brian
    
    Digital Oakland Support
    California.
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2241.1NETCAD::B_CRONINWed May 03 1995 14:175
    
    Which LEDs are blinking? The front panel should be all M ports, and
    no lights should be blinking (especially blinking green). For instance,
    if the blinking lights are on the modpmd cards, is it the PHY LED or
    the port LED (the one on then right). 
2241.2It's a blinkin mystery ???MARIN::JONESWed May 03 1995 18:0214
    
    All LED's on the top of the unit are green (3 of them) .. the M ports
    are all off ... so that's it ... we've already had someone check out
    the actual cabling running to faceplates from this unit .. it checks
    out ok .. we have tried hooking up a system directly to the unit with
    Digital Cat 5 supplied cable ... no joy ... the lights on the FDDI
    card just keep blinkin .. !!
    
    Any thoughts...
    
    thanks
    
    /Brian
    
2241.3NETCAD::B_CRONINWed May 03 1995 19:4527
    
    
    
    
    I think that the lights on the NICs blink when they are not connected,
    that explains some of my confusion. The concentrator's PHY lights are off
    if there is no connection, and green if there is a completed
    connection. 
    
    My next thought is that the patch cables may be wrong. There needs to
    be an odd number of crossovers in the cable plant between the 
    NIC and the concentrator. Its possible that you are getting burned 
    by that. Pins 1 and 2 are the tranmitter, 7&8 are the receiver. There
    needs to be an odd number of crossovers in the cable plant to get the
    two ends to see each other. 
    
    Try this: Gather up the two patch cables used in this link. Connect
    together 2 M ports of the concentrator using each patch cable. If the
    PHY lights of the ports blink orange, indicating that the M to 
    M connection is being rejected, the cable has a crossover in it. 
    If the cable does not have a crossover, no lights will light up 
    (as the receiver doesn't see the transmitter). Once you know how many 
    patch cables have crossovers, make sure that the cable plant matches 
    the number you need to get an odd number of crossovers. 
    
    
    
2241.4No lights .. no action !MARIN::JONESWed May 03 1995 20:2510
    Gettin no lights what so ever when I connect to M ports up with the
    patch cable ... RJ45 .. 8 wires, according to defta-ua manual, pins
    1 & 2 are RX+,RX- respectively, and 3,6 are TX+,TX- respectively ...
    
    Looking at this Cat 5 cable I have , the wires are straight thru with
    no cross overing from what I can see going by the coloring...
    
    Is this the problem ...?????????
    
    /Brian
2241.5NETCAD::B_CRONINThu May 04 1995 14:1710
    
    Yes, it looks like you may have patch cablkes that do not make any 
    connection. If the cables are straight thru, that is the problem. 
    
    You will need 1 crossover cable, and 1 straight through cable, 
    assuming (as is usually the case) the cable plant is a straight
    through connection. 
    
    Sorry, I don't remember the number of the crossover cable, but I'm
    pretty sure we sell it by now. 
2241.6Is that so...~~!!\MARIN::JONESThu May 04 1995 20:183
    Thanks ... I'll try and get hold of a BN25H cable then...
    
    /Brian
2241.7The defta Manual is incorrect.NPSS::BUZYNSKIFri May 05 1995 11:1410
        The correct cable to use is the BN25H-03. The DEFTA manual (figure B-2)
        is incorrect. The RJ45 pin assignments are:
    
        Pin             Assignment
        ------------------------
         1                  TX+
         2                  TX-
         7                  RX+
         8                  RX-