ABB Relion 670 series, Technical Reference Manual, Page: 1127 / 1232

• Unconnected: No ground of the IO-part · .
• Soft grounded: The IO is connected to the GND with an RC net parallel with a MOV
19.2.15.3 Technical data
Table 707: Galvanic RS485 communication module
Quantity Range or value
Communication speed 2400–19200 bauds
External connectors RS-485 6-pole connector
Soft ground 2-pole connector
19.2.16 Optical ethernet module (OEM)
19.2.16.1 Introduction
The optical fast-ethernet module is used to connect an IED to the communication buses
(like the station bus) that use the IEC 61850-8-1 protocol (OEM rear port A, B). The
process bus use the IEC 61850-9-2LE protocol (OEM rear port C, D). The module has
one or two optical ports with ST connectors.
19.2.16.2 Functionality
The Optical Ethernet module (OEM) is used when communication systems according
to IEC61850–8–1 have been implemented.
19.2.16.3 Design
The Optical Ethernet module (OEM) is a PMC card and mounted as a mezzanine card
on the ADM. The OEM is a 100base Fx module and available as a single channel or
double channel unit.
1MRK505222-UUS C
Section 19
IED hardware
1121
Technical reference manual