Symbol 5521A from IEC 60417 - Title/Meaning: Video input/output Function/description: To identify video equipment input/output controls and connecting terminals.[]This symbol applies also when an audio signal is included.
Additional information: 
To qualify this symbol, symbols such as 5048, the analogue sign or the digital sign may be added, in accordance with the user's documentation.
The outline of the symbol may be interrupted at the entrance/exit of the signal as shown in 5521B
Published in: Supplement M, 1994
Own work using: iso.org/obp/graphics/grs/e58992da-afca-46b7-a065-c5ab44aad330 200.png
Vectorization:  Mrmw