What is the difference between Eon-ID series and Eon/Eon-LT series of products?

The primary difference is that the Eon and Eon-LT require a computer to operate them; Eon-ID does not. Eon-ID contains an internal CPU and touchscreen, making it also rackmountable. With Eon-ID, log files can be saved to a external USB drive and viewed on a standard computer. The Eon and Eon-LT use RS232 to communicate to an external device.