Medias Mediatrix 1204, Reference Manual

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Appendix C - Cabling Considerations RJ-45 Cable
308 Mediatrix 1204
The RJ-45 cable uses two pairs of wires: one pair for transmission and the second pair for reception. It is wired
so that pins 1 & 2 are on one twisted pair and pins 3 & 6 are on a second pair according to common wiring
standards which meet the EIA/TIA T568A and T568B requirements.
Figure 69: Straight Through Connectivity
Pin Name And Function
The following is the meaning of each pin in a RJ-45 cable.
Crossover Cable
A RJ-45 crossover cable is used when only two systems are to be connected to each other, peer to peer, at
the Ethernet Cards by “crossing over” (reversing) their respective pin contacts. An example would be
connecting two computers together to create a network. The crossover eliminates the need for a hub when
connecting two computers. A crossover cable may also be required when connecting a hub to a hub, or a
transceiver to transceiver or repeater to repeater. When connecting a hub to a transceiver, a straight through
cable is always used.
A crossover cable is sometimes called a null modem. The coloured wires at either end are put into different
pin numbers, or crossed over.
Figure 70: Crossover Connectivity
Table 192: Pin Name and Function
Pin # Name Function
1 Transmit Data Plus The positive signal for the TD differential pair. This signal contains the serial
output data stream transmitted onto the network.
2 Transmit Data Minus The negative signal for the TD differential pair. This contains the same
output as pin 1.
3 Receive Data Plus The positive signal for the RD differential pair. This signal contains the serial
input data stream received from the network.
4 not connected
5 not connected
6 Receive data minus The negative signal for the RD differential pair. This signal contains the
same input as pin 3.
7 not connected
8 not connected
Pin 1
Pin 2
Pin 3
Pin 6
Pin 1
Pin 2
Pin 3
Pin 6
Note:
This is not an IEEE supported configuration and should be used for test purposes only.
1- TX+
2- TX-
3- RC+
6- RC-
TX+ -1
TX- -2
RC+ -3
RC- -6