An Aries EPL unit (PE) can be converted to a drive/controller unit via downloading the CE operating system when connected through the ACR9030 or 9040.
Then you may connect directly to the Aries CE unit. But if you've downloaded the operating system change and come back, how do you know it's a CE or a PE?
The PE units' left LED indicates the EPL status and will be a fast green flash when the EPL network has been reset (turned off). This will change to a solid green when connected to 9030/9040. So if the unit is not connected via the ethernet connections and the unit has a fast-green flicker, it's an PE unit.
The CE units' left LED (ethernet status) will be green (constant), red or green/red based on the port connections. If there is no connection, the LED will be off.