@Gerco 

I guess they are incompatible. You'd better use both modules from the same brand.

@Somnus 

Thank you for your reply.

I fear that this is indeed the case.

I am not sure if I can find two SFP modules of the same brand since one device is a TP-link and the other a Netgear. The manual says to use AGM731F coded module. Now, I am no techie but it's my guess that the manufactor/brand should be irrelevant, the module should just have this AGM731F coding. Or are there other physical aspects of the module that can indeed play a role? 

@Gerco 

I think @Somnus means only SFP from the same brand (not switches and SFP from same brand).

@Libik 

That's what I understood indeed, maybe my reply was not clear enough on this. 

I have spoken with the company I bought the network stuff from and both them and me guess we have a pretty uncommon situation where two sfp modules are not compatible with each other. And to answer the question you might want to ask. In both Netgear and Tp-link the port-settings are set to 1000M because that is the speed they need to connect with. 

I ordered a Tp-link switch with the same SFP module as my TPlink T1700 switch uses for 1000M connections (I also have a second TP-link switch T1700 that connects with 10G, SFP+,  acting as a backbone in my house). My neighbor needs a new switch and he will be taking over my Netgear since the other switch he is using does connect to the NetGear SFP module.