I only deduced that because the instructions (used to) say you plugged the SPC into LAN with a specific private IP, than could plug in the Emizon anywhere else
on the same LAN with another specific private IP. So, it must have been using native format to get to the Emizon? There was no mention of RS232. dial capture etc...
Yup, uses EDP over IP (Bacronymed Enhanced, presumably once Europlex)
http://www.emizon.com/images/PCGs/Siemens_SPC_Ethernet.pdf