Time Machine has Ethernet pass through ports❓

"Pass through" is how you might describe an Ethernet Hub. The Apple device is similar, but somewhat more complex in a number of ways.

The Apple Time Capsule and similar-looking Airport Base Station features three "regular" Ethernet ports. The device itself implements the "store and forward" features of an Ethernet Switch. Since it does "store and forward" rather than just pass-through, it can do more clever things. It can connect two devices at different speeds. It avoids taking up network bandwidth forwarding packets that are damaged or invalid. It can connect devices on Wi-Fi to devices on Ethernet 9and the other way round as well). It uses all its ports to create a single local Network made up of both Wired (Ethernet) and Wireless (Wi-Fi).

Packets sent to these Ethernet ports that are bound for other devices on the local Subnet are forwarded to the other Ethernet ports, and are also broadcast on your local Wi-FiI. (an example might be a local Ethernet network printer.)

Packets sent to the Ethernet ports that are bound for the Internet are processed with the Router portion of the Base Station, have their addresses translated with Network Address Translation, and forwarded to the WAN Ethernet port -- presumably to your Internet connection. The Router acts as the Agent for your computer(s) on the Internet.

if what I wrote just sounds like "word-salad" try asking a more specific question.