Symbol 5989 from IEC 60417 - Title/Meaning: Telephone line Function/description: To identify the terminals for any commumication equipment to be connected to the telephone line.
Additional information: 
Published in: 3C/1496/FDIS, 3C/1508/RVD
Own work using: iso.org/obp/graphics/grs/0c13e6a4-e191-4b44-9cad-8a11a8061123 200.png
Vectorization:  Mrmw