ABB RELION 620 Series Technical Manual page 910

Section 14
Protection relay's physical connections
14.3.7.3
904
COM0033-COM0034 jumper locations and connections
The optional communication modules include support for optical ST serial
communication (X9 connector). The fibre-optic ST connection uses the COM1 port.
GUID-4CAF22E5-1491-44EF-BFC7-45017DED68F4 V1 EN
Figure 465: Jumper connections on communication module COM0033
1MAC504801-IB E
3 3
2 2
X15 X24
1 1
Technical Manual
620 series ANSI