Symbol 6442 from IEC 60417 - Title/Meaning: Communication ports, galvanical port Function/description: To indicate the galvanical port, unidirectional.
Additional information: 
For technical details, see IEC 62052-11.
Own work using: iso.org/obp/graphics/grs/8ec6c9d9-5403-42c4-b792-48bf0c588bd2 200.png
Vectorization:  Mrmw