Etalon ethernet isolator.

[K4680]

Thanks for that K4680.  So if I am interpreting this correctly, this is not passive filtering per Antoine's concerns. (Note that Antoine did not say it was passive filtering, he was simply concerned it might be)  It simply allows the data through unhindered, whilst offering complete isolation from spurious electrical noise and grounding.  Please correct me someone if I have got this wrong!

So if I have got this right, it cirtainly cannot do anything negative, and if electrical noise or grounding are an issue in a system, the issue is eliminated.

Hello Confused, this is so ok!
An extract from the data sheet:
Network insulators of the type EMOSAFE EN-30 interrupt any metal-conducting connection between devices that are connected to each other via a copper-guided Ethernet cabling. They prevent potential leakage currents and protect connected devices and their users from transient overvoltages, which can be coupled directly, capacitively or inductively into the network line due to installation faults, lightning strikes, switching operations, electrostatic discharges.
3 APPLICATIONS
3.1 PATIENT PROTECTION
Galvanic separation of the Ethernet interfaces from medical electrical devices or systems, in which patients must be protected against hazardous leakage currents in accordance with standard requirements.
3.2 EQUIPMENT PROTECTION
Protection of particularly valuable equipment against hum and overvoltage from the network periphery.
3.3 TECHNOLOGY
Protection of electrical measuring and monitoring devices against external and interference voltages from the Ethernet cabling.
3.4 AUDIO
Reduction of low-frequency alternating voltages (mains ripples), which are caused by the network connection, to an extent which is no longer perceptible.