What simplex panels are able to be networked and to what network?

From what I understand is that there are 3 different networks. I have a very low understanding of what panels are comparable with what network. ES net (4100es, 4010es, 4017es, 4007es), the 4120 network (4100es, 4017es?, 4007es, 4100U, 4010, 4008?, 4006?, 4120, 4020?, 4100+?, 4002) and the 2120 (4020?, 4100?, 4120?)

2120 is not a network type that exists.

In regards to the other two – mostly correct.

ES Net networks are exclusive to the 4100ES, 4010ES, 4017ES and 4007ES, and new gen NSI panels, as well as 4190 TrueSite Workstations/Incident Commanders. These networks use different hardware than the 4120 network does, and support a few more features (such as connectivity over Ethernet). They also still, of course, support fiber optic (multiple types) and wired media.

4120 (now legacy, they are officially ‘discontinued’ by Simplex) networks officially support 4100ES, 4100U, 4100+, 4100 classic, 4010ES, 4007ES, 4010 classic, 4020, 4002, 2120, NPU, 4190 TrueSite Workstation/Incident Commanders (and IMS, aka the older TSW), 2500 NDU, and old gen NSI panels.
Older systems (such as the 4100+/classic or 4020) must be updated to a newer firmware revision in order to play nicely with the rest of the network.

There are also several NDU types compatible with each network, such as the ES Net NDU and 4120 NDU, respectively.

So I’m trying to finally fully understand all of this. The 4100 classic is compatible with the 4120 network? I’m under the impression that the network was made for the 4100+.

A data sheet references under optional modules “Simplex 2120 Interface” and “Can be configured to communicate with a host 2120 Multiplex System using 2-wire, 2120 communications (DC Comm.)” does this mean it’s a replacement for the BMUX and or it can function as a transponder?

The 2120 interface card simply allows the 4100 Classic and 2120 BMUX to communicate back and forth to one another. The 4100 Classic was usually not used as a replacement for the 2120 because they were in production at the same.

4100 Classics may be added to a 4120 network if they are on REV 6.04 or later.

Edit: Later 2120 BMUX are also capable of interfacing with a 4120 network

Well that changes a literal ton from how I understand my university’s fire alarm systems, thank you