Allied Telesis x530 Series Installation Manual page 185

If the problem is with two BiDi (bi-directional) transceivers, refer to

their data sheets to verify that their transmission and reception
frequencies are opposite each other. For instance, a BiDi
transceiver that transmits and receives at 1310nm and 1550nm,
respectively, has to be connected to a transceiver that transmits
and receives at 1550nm and 1310nm, respectively. Two BiDi
transceivers will not establish a link if they transmit and receive at
the same frequencies.
Problem 5: The SHOW STACK command is not displaying all the
switches in the stack.
Solutions: If you are using 10Gbps ports for the stack trunk, try the
following:
Verify that the stacking ports are properly cabled. Refer to Chapter

9, "Cabling the Networking Ports" on page 173.
If you are using SFP+ transceivers for the stack trunk, verify that

they are fully inserted into the transceiver ports.
If you are using SPI0TW direct connect twinax cables, verify that

they are from Allied Telesis. The trunk will not work with cables
from other network equipment manufacturers.
Verify that the VCStack is activated on the switches. For

instructions refer to "Verifying the Stack" on page 171.
Verify the switches have the same software version, AlliedWare

Plus v5.5.1-1.2.
Problem 6: Network performance between a copper port on the switch
and a network device is slow.
Solution: There might be a duplex mode mismatch between the port and
the network device. This can occur when a copper port using Auto-
Negotiation is connected to a remote device that has a fixed speed of 10
or 100Mbps and a fixed duplex mode of full duplex. If this is the cause of
the problem, adjust the duplex mode of the port on the network device or
switch so that both ports are using the same duplex mode. You can use
either the LEDs or management software on the switch to determine the
duplex mode settings of the ports. The LEDs are described in "LEDs" on
page 40.
Problem 7: The switch functions intermittently.
Solutions: Check the system hardware status through the management
software:
Use the SHOW SYSTEM ENVIRONMENT command in the

Privileged Exec mode to verify that the input voltage from the
power source to the switch is stable and within the approved
operating range. The unit will shut down if the input voltage
x530 Series Installation Guide for Virtual Chassis Stacking
185