Looking for spare EWSD SN (switching network)

I’m currently trying to help some friends at an undisclosed museum in Germany to bring back into operation the remains of a DIVF (Fernvermittlunggstelle). While most parts seem to be preserved, sadly the SN (Switching Network, German: Koppelnetz) is missing.

In case somebody has a source where a spare SN could be recovered from, it would be very much appreciated. I’d assume a minimal SN is sufficient, there’s no need for a lot of switching capacity in a museum…

Thanks in advance for your help!