Hub and Switch terminology

What is the difference between Ports and nodes when we are talking about Hub and switches.
Is Frame and Signal the same thing?

Hub is mostly used for connecting different devices. It does nothing but transfer signals to other systems. There is no concept of ports in hubs, it just takes the packet from the upper layers (TCP/IP) and sends it to another system. If you see it in a general way, the packets formed in the upper layers of TCP/IP are at the end converted into signals to be sent across the devices. It’s the functionality of different devices that separates the packets. Switches are used at the data link layer, routers are used at network layers, and hubs are used at the physical layer. In the end, everything leaving your system is converted to signals and sent to other systems using the devices at the physical layer.