Symbol 5504 from IEC 60417 - Title/Meaning: Repeat last call Function/description: To identify the control by which the last number dialled is called again (e.g. if it was previously engaged).[]This service can be repeated (e.g. if still engaged).
Additional information: 
See ITU-T Recommendation E.121
Published in: Supplement J, 1990
Own work using: iso.org/obp/graphics/grs/51be05ed-b71d-4f67-bc19-e154212e142f 200.png
Vectorization:  Mrmw