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From: jfinke@itsgw.rpi.edu (Jon Finke)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Thick or Thin
Summary: Slide lock is evil
Keywords: thinnet, thicknet, costs, transceivers, xcvrs
Message-ID: <1989Oct4.153141.19593@rpi.edu>
Date: 4 Oct 89 15:31:41 GMT
References: <42457@sgi.sgi.com> <2781@jhunix.HCF.JHU.EDU> <4028@phri.UUCP>
Organization: Rensselaer Polytechnic Institute, Troy NY
Lines: 33

In <4028@phri.UUCP> roy@phri.UUCP (Roy Smith) writes:
>	I suppose the thick trunk cable is pretty tough, and the way the
>typical vampire tap xciever connects to the cable is pretty good, but the
>stupid D-15 connectors for the xciever drop cable is a disaster.  The
>xciever ends don't give us any trouble because they are hidden away in a
>ceiling or wall where nobody can touch them, and we have the drop cable
>firmly lashed to the trunk cable with 2 or 3 nylon cable ties to keep them
I have had cables like this cause problems when someone else pulls
a wire throught the ceiling, or opens the ceiling for any other reason.

>from shifting.  On the other hand, the connection from the xciever cable to
>the workstations is our single most common cause of network failures.  You
>just can't take a stiff heavy cable and expect it to stay attached to a
>flimsy slide-lock widget, especialy where the cable and/or the workstation
>are capable of being moved by accident.

We also found this to be our most common ethernet failure at RPI.
It is now standard practice here to replace slide lock hardware
with screw lock hardware for all installations.  We mostly use
thinnet, but enough equipment comes through with the DB15s
that we still convert when it arrives.   About half the equipment can
be modified without opening the covers.   I don't think we have had
a failure of a screw lock connected DB15.  We also make a lot of our
own drop cables, that way we can get the correct hoods and hardware
for them.  Some cables can also be modified for screwlock hardware.
This does preclude the use of right angle cables, but that seems a 
small price to pay for the greatly increased reliability.

-- 
Jon Finke                              jfinke@itsgw.rpi.edu
Network Systems Engineer               USERB239@RPITSMTS.BITNET
Information Technology Services        518 276 8185 (voice)
Rensselaer Polytechnic Institute       518 276 2809 (fax)