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Home > Archive > CCNA > June 2001 > crossover cable
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| sauser 2001-06-24, 6:52 pm |
| Hmm i was redaing an artcile about cables pin outs and i have a question what is difference between TX+ and TX-? | |
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| sauser 2001-06-24, 7:40 pm |
| so what you mean is that it is just a return wire to the ground on the power supply? | |
| strikeattack 2001-06-25, 7:22 am |
| Yes, the TX and RX do not share a common ground. They both have their own negative return wire. | |
| lennon57 2001-06-25, 10:34 am |
| I was trying to make the relationship for the signals. You always have a start and end point. With electrical signals, you have to have a reference line.
+5 + + + + T+ ( + for bit high)
0=== ==== ==== ===== == T- ( = for bit low)
Time---------------->
As you can tell, T- is the 0 level, T+ is the +5 level.
Without the T-, there is no reference, and is not mesurable.
Therefore, as time progresses, the circuitry
reference's 0 (or T-) to tell when it get's a bit high +5v (or T+). As strike mentioned, they dont share a common ground, and all the isolation is taken care of in the physical level circuitry.
Hoping this graphic makes it a bit clearer...
(pun intended) |
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