R50 recorders were the original 'old' recorder that required a separate CPS to enable network connectivity.
The CPS was configured with the relevant network information to enable connectivity between the recorder and the network.
R50's were very quickly superseded by the R50N network recorder, which enabled the recorder to be connected directly to any RJ45 network socket. These recorders could be configured directly with the relevant network information to ensure connectivity. In short the R50N did away with the CPS meaning that there was less H/W to install and was cheaper.
Infinity networks use the open standard TCP/IP protocol and therefore, there is nothing proprietary about how the network operates meaning that standard components can be sourced to ensure connectivity.
The problem here is that you have a first generation recorder.
You maybe better off by purchasing a replacement network recorder and adding this to your network. But, don't forget you will need to configure it with new network settings to ensure the network can 'see' it.