I need a way to turn off/on about 20 relays or FETs using RS-232 codes. (I do not want to program a generic microcontroller, I want a dedicated device that is designed to do switching only.) I notice that there products called "relay controllers" like this: https://store.ncd.io/product/rs-232-8-channel-dpdt-relay-controller-with-serial-interface/
However the problem with this is that it has the relays built into it. In our case, which is a hi-fi audio application we are using specialized low-noise relays, so we need a board that kind of does what this does, take RS-232 codes and turn switches off and on, but does NOT have the switches or relays on the board. Is there such a thing, and if so what is the terminology that is used for it?
Once again: I DO NOT WANT TO PROGRAM ANYTHING and I do not want to use a programmable device. I need a module type that accepts codes or messages via RS-232 and turns lines high or low accordingly. What is this called?
I have tried terms like "rs-232 switching controller", "switching board", "switching IC", "relay controller", etc, and the closest thing I can get is stuff like the below with the switches built into the board.