Half or Full Duplex in SLC 5/05

In setting up channel 1, there are four choices for half or full duplex and 10 or 100 Mbps. 10 Mbps is plenty fast so I chose that.
Channel 1 is connected to a Panelview Plus 700. I've read the help menu but I still don't know whether to choose half or full duplex. What's the difference? I thought half duplex was one-way communication and full duplex was two-way communication. I would think I need full duplex as the PLC sends data to the screen but there are also screen objects like pushbuttons and keypad entries that send data to the PLC.
The PLC is an L553, Series C.
What are the various choices for?

Well, half-duplex does not neccessarily mean one-way communications. The older SLC 5/05's were fixed at 10M half-duplex and certainly had bi-directional (XMIT/RCV) comms. On the newer 5/05's, I have always just checked the "Auto Negotiate" box to the left of the port speed drop down menu.

Too many options.

I would set up the SLC5/05 full duplex if the switch or router supports it. Almost all should. The router/switch should be able to negotiate the best rate and duplex for the other devices.

If not the lowest common denomimator is 10mbs and half duplex.

The SLC5/05 should be able to auto negotiate the connection speed and whether it is full or half duplex. I don't see why it can't. This is something that you shouldn't have to mess with.

There are BIG advantages to using full duplex. The device can be sending and recieving data at the same time providing it has buffers in the Ethernet chip that can hold all this data.
A half duplex device will report a collision if it sends data at the same time it is receiving data. Thereore the biggest advantage using full duplex is a reduction in collisions.

Sending and recieving data at 10 times the speed also reduces collisions becuase a message takes 10 times less wire time.