Allied Telesis AT-PBC18 - Manual (Page 48)

Installing a Media Converter Module
48
Half-duplex and
Full-duplex Mode
Duplex mode refers to the way an end-node sends and receives data on
the network. An end-node that is operating in half-duplex mode can
either send data or receive data, but it cannot do both at the same time.
An end-node that is operating in full-duplex mode can send and receive
data simultaneously. The best network performance is achieved when
an end-node can operate at full-duplex, since the end-node is able to
both send and receive data simultaneously.
All of the PowerBlade Media Converters are transparent to the duplex
mode of the end-nodes that are connected to their two ports. That is, a
PowerBlade Media Converter can operate with end-nodes operating at
either half-duplex or full-duplex mode. However, the two end-nodes
connected to the ports on a PowerBlade Media Converter must operate
with the same duplex mode.
For example, assume that the 100Base-TX port on an AT-PB102 is
connected to a port on an AT-FH705E hub configured for half-duplex
operation, while the 100Base-FX port is connected to a port on an
AT-8224XL switch configured for full-duplex operation. This would be an
invalid configuration and could adversely impact the performance of the
network. Either the port on the AT-FH705E hub connected to the
100Base-TX port would have to be changed to full-duplex (if it supports
that capability), or the port on the AT-8224XL switch connected to the
100Base-FX port would need to be changed to half-duplex.