[Sussex] Connecting Slackware 10.1 to Slackware 10.1 [Was: Connecting SuSE 9.2 to Windows XP]

[John Crowhurst]

On Thu, April 14, 2005 10:36, Steve Dobson said:
> Ronan
>
> On Thu, Apr 14, 2005 at 09:06:44AM +0100, Ronan Chilvers wrote:
>> steve at dobson.org wrote:
>> > Okay, so you only need four of the lines for networking but
>> > they are not the same four lines as used by an RJ45.  You can
>>
>> Or 8 if you want 100Mbps.
>
> How are the 8 lines used?

According to pinouts.ru they are:

1 TX+
2 TX-
3 RX+
4 N/C
5 N/C
6 RX-
7 N/C
8 N/C

This is the same for 10Base-T and 100Base-TX. 100Base-T4 however is:

1 TX_D1+
2 TX_D1-
3 RX_D2+
4 BI_D3+
5 BI_D3-
6 RX_D2-
7 BI_D4+
8 BI_D4-

And 1000Base is:

1 BI_DA+
2 BI_DA-
3 BI_DB+
4 BI_DC+
5 BI_DC-
6 BI_DB-
7 BI_DD+
8 BI_DD-


> I thought that 100Mbps was due to the quality of the wire not to
> the number.

Its all down to the grade of wire, type of shielding etc.

> I ask because I think you can have Power Over Ethernet (PoE) over
> standard Cat5(E) cable.  You need a special (and expensive) switch
> but the system can be used in existing installations.  I thought
> the PoE used two unused lines to provide the power.

PoE uses 2 pairs, but both pairs are wired together to provide more
current capacity. 4 & 5 form +VE, 7 & 8 form -VE.

--
John