Siemens ESM - Manual (Page 28)

Introduction
Industrial Ethernet OSM/ESM
24 C79000-Z8976-C068-10
Properties of the ESM TP40
Ports 4 x 10/100 Mbps
autonegotiation/autocrossover ports
with TP connectors (RJ-45 jacks)
Maximum distance between two ESMs 100 m
Maximum ring span with 50 ESMs 5 km
Digital Inputs 4 x DC 24V