| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 2219.1 | | netrix.lkg.dec.com::thomas | The Code Warrior | Mon Feb 10 1997 17:46 | 4 |
| I bet the customer is not really certified cat5 cables. He should rent a
tester and see what the cables really. I bet they are cat3.
(I use cat5 and see no glitches and my run is ~40 meters).
|
| 2219.2 | | NETCAD::STEFANI | FDDI Adapters R Us | Tue Feb 11 1997 08:49 | 23 |
| >> I have a customer who says he sees lots of mac error levels on his
>> Alpha500 workstations when running them on UTP, CDDI or whatever this
>> setup is being called these days. He is running digital unix 3.2d,
The standard is ANSI TP-PMD, although a common marketing term for running FDDI
over Category 5 UTP cabling is "CDDI".
>> I have been told that UTP is notorious for being sensitive to any
>> electrical noise and one person has told me they have never seen
>> networks over copper wires in an UTP environment to run cleanly. Is
I don't know about that, but there are issues we're investigating with UTP
components across many products (both FDDI and Fast Ethernet). My suggestion
would be to IPMT this.
>> this something the customer will have "to live with" if he prefers the
>> less expensive copper to true FDDI?
----------
"True FDDI" supports many PMD types, UTP is just one of them. I wouldn't say
that running FDDI over copper is any less "FDDI" than running it over fiber.
- Larry
|
| 2219.3 | | NPSS::WADE | Network Systems Support | Tue Feb 11 1997 08:51 | 8 |
| What is the customer seeing for LEM counts and LER estimate on the
DECconcentrator 900 ports connected to the Alphas?
Bill Wade
Network Product Support
|
| 2219.4 | Pay attention to quality of cable installation work... | NETCAD::BATTERSBY | | Tue Feb 11 1997 09:55 | 18 |
| It should be emphasized to the customer that it isn't the
that the UTP Cat-5 cable in of *itself* is sensitive to
noise, rather that care should be taken to route UTP cable
in such a way so as to avoid long parallel runs along side
AC electrical wiring not encased in metal conduit, and to avoid
flourescent light fixtures, electric motors etc. Almost any
cable type can be found to be sensitive to electrical interference
and mechanical damage if it is installed improperly.
Most competent commercial cable installers will adhere to the
above type of guidelines, and will also certify their work by
testing afterwards using an approved Category 5 cable tester.
So basically, the customer should be concerned with the quality
of the cable installation work, whether they do it themselves
to save money, or pay someone else to do it.
Bob
|
| 2219.5 | But what to do...?? | UTRTSC::DEKKER | | Fri Mar 07 1997 15:36 | 15 |
| re. 4
To my understanding the signalling is (or at least should be)
differential. Therefor is noise is induced it should not matter to the
receiver of the signal.
The thing is that we have a couple of customers which also have
problems using UTP (cat5.) To my knowledge the manuals do *not* warn
you for using this type of cabling in an industrial environment.
So the point is: how can we cure this situation? For new
'industrial-customers' and what for the existing bad functioning utp
rings.
Ton.
|