Command RegisterDevice :

Parameters for a device connected to the prologix. This will tell
the server which communication settings to use with the
device server you are calling the command from.
The values are:

0: gpib address
1: auto: (0|1)
2: eoi (0|1)
3. eos (0|1|2|3)
4: eot_enable (0|1)
5: eot_char (ascii value)
6: read_tmo_ms (1-3000)

For details check the prologix docs.

If you do not call this function from your device server default
settings will be used. You can overwrite those with property
DefaultConfig, if you don`t, they are:

auto: 0
eoi: 1
eos: 2
eot_enable: 0
eot_char: 0
read_tmo_ms: 500

RegisterDevice Definition
Input Argument	Tango::DEVVAR_LONGARRAY
Output Argument	Tango::DEV_VOID
DisplayLevel	OPERATOR	..
Inherited	false	..
Abstract	false	..
Polling Period	Not polled	..
Command NOT allowed for	FAULT	..