Exact difference between TDMA and TDM

[iVenky]

I have seen many threads on this topic and I have come to some conclusions.

In TDM we share a resource such as a cable and there is a physical switch that switches between many channels.

In TDMA there is no such cable but here the bandwidth of the channel is shared by many users. So here there is no need for any physical link and at the same time the nodes may be at different places.

The same goes for FDMA and FDM.

Is my definition correct?

Thanks in advance.

 

[rhearty1]

Here's what wikipedia says:
"TDMA is a type of Time-division multiplexing, with the special point that instead of having one transmitter connected to one receiver, there are multiple transmitters. In the case of the uplink from a mobile phone to a base station this becomes particularly difficult because the mobile phone can move around and vary the timing advance required to make its transmission match the gap in transmission from its peers."

"Frequency-division multiplexing (FDM) is also distinct from FDMA. FDM is a physical layer technique that combines and transmits low-bandwidth channels through a high-bandwidth channel. FDMA, on the other hand, is an access method in the data link layer."