Junger Audio d07 - Digital Transmission Processor - Manual (Page 29)

A 4.2. – operation via web browser
4.2.5 SETTING > GPI/O
GPIs are useful if you want to recall settings remotely e.g. by presets.
The d07 has 8 physical GPIs (opto coupler) which can be assigned functions of the d07.
GPOs (Tallies) are useful if you want to monitor status information of the d07.
The d07 has 8 physical GPOs (relays) which can be assigned conditions of the d07.