| Title: | DEChub/HUBwatch/PROBEwatch CONFERENCE |
| Notice: | Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7 |
| Moderator: | NETCAD::COLELLA DT |
| 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 |
Hello all,
I am very confuse about RJ45 ports on VNswitch900EX.
What is cable type when I connected to PC (for 12 Ethernet) ?
What is cable type when I connected to PC (for 2 Fast Ethernet) ?
I hear that 12 ports ethernet support auto-polarity.
Is it ture ?
Does the Fast-Ethernet port support Auto-polarity ?
Best Regards,
Wittaya J.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 4300.1 | Yes. | NETCAD::PAGLIARO | Rich Pagliaro, Networks BU, HPN | Mon Mar 24 1997 10:09 | 23 |
>> What is cable type when I connected to PC (for 12 Ethernet) ?
Use a straight-thru cable to connect a PC to one of the VNswitch's 12
10Mb/s-only Ethernet ports.
>> What is cable type when I connected to PC (for 2 Fast Ethernet) ?
Use a cross-over cable to connect a PC to one of the VNswitch's
100BASE-TX Fast Ethernet ports.
>> I hear that 12 ports ethernet support auto-polarity.
>> Is it ture ?
>> Does the Fast-Ethernet port support Auto-polarity ?
The 12 10Mb/s-only Ethernet ports on the VNswitch 900 automatically
correct reversed receive polarity errors. The 100Base-TX Fast Ethernet
ports, WHEN THEY ARE OPERATING IN 10Mb/s 10BASE-T MODE will also
correct reversed receive polarity errors.
Please do not confuse the ability to correct reversed polarity on the
receive (RX +/-) pair with the need to cross-connect the Receive and
Transmit pairs.
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| 4300.2 | 100BASE-TX does not have polarity | NETCAD::PAGLIARO | Rich Pagliaro, Networks BU, HPN | Mon Mar 24 1997 10:27 | 13 |
More information regarding polarity correction on Fast Ethernet... In
the previous reply I stated that the VNswitch 900's Fast Ethernet ports
will correct reversed receive polarity WHEN THEY ARE OPERATING IN
10Mb/s 10BASE-T mode. This begs the question, what about when such
ports are operating in 100Mb/s 100BASE-TX mode? The answer here is that
there is no polarity to worry about.
The 100BASE-TX standard borrowed a lot from the FDDI TP-PMD standard.
They both use a code called MLT-3, in which the transitions encode the
data. It is the transition itself, not the polarity of the transition
that carries the data. Because of this, there is no polarity like there
is with 10base-t, hence, no need to worry about it being reversed.
(This information was copied from note 942.3).
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