Twisted Pair Cable - Allied Telesis CentreCOM AT-270T User Manual

Receive — Indicates packets are received from the UTP media.
Polarity —This LED will extinguish if the auto polarity correction has taken place.
This +- signal reversal takes place on the RD- and RD+ signal lines only. This LED
is normally ON.
SQE Test—Heartbeat status LED is ON if Heartbeat is enabled and OFF if
Heartbeat is disabled.
Collision—Indicates a Collision has occurred.

Twisted Pair Cable

There are several types of twisted pair cables. The IEEE 802.3 specification states
that the maximum length of a 10BASE-T link segment is 100 meters (328 ft.) of
UTP wiring. For network reliability, these limits should not be exceeded.
Remember, if another AT-270T MAU is connected to the opposite end of the link,
the UTP cabling must be crossed. i.e., RD- and RD+ signals must be swapped with
the TD- and TD+ signals respectively. The UTP cable should be 26 to 22 AWG (0.4
to 0.6 mm) wire in a multi-wire cable with 100
should have the TD pair and the RD pair crossed as shown below.
Pin No. Signal Name
1
2
3
4
Pin No.
1 LOGIC GND
2 COL +
3 TX-
4 LOGIC GND
5 RX+
6 POWER RETURN
7 N/C
8 LOGIC GND
Table 1: RJ45 Connector Pin-Out
TD+
TD-
RD+
Not Used
Table 2: AUI Pin-Out
Signal Name
impedance. The UTP link segment
Pin No.
5
6
7
8
Pin No.
9 COL-
10 TX-
11 LOGIC GND
12 RX-
13 POWER +12 Vdc
14 LOGIC GND
15 N/C
Signal Name
Not Used
RD-
Not Used
Not Used
Signal Name