Mitel TA7102 Installation Manual page 39

Table 11: Pin Name and Function
Pin #
1
2
3
4
5
6
7
8
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.
Note: This is not an IEEE supported configuration and should be used for test purposes only.
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 8: Crossover Connectivity
153/1531-ANF 901 14 B 2017-03-08
Name
Transmit Data
Plus
Transmit Data
Minus
Receive Data Plus
not connected
not connected
Receive data
minus
not connected
not connected
1- TX+
2- TX-
3- RC+
6- RC-
Function
Positive signal for the TD differential pair. This signal
contains the serial output data stream transmitted onto the
network.
Negative signal for the TD differential pair. This contains the
same output as pin 1.
Positive signal for the RD differential pair. This signal
contains the serial input data stream received from the
network.
Negative signal for the RD differential pair. This signal
contains the same input as pin 3.
TX+ -1
TX- -2
RC+ -3
RC- -6
TA7102 Hardware Installation
39