NEC MultiSync S521 - Manual (Page 11)

English-9
English
Kensington Lock
For security and theft prevention.
EXTERNAL SPEAKER TERMINAL
To output the audio signal from AUDIO 1, 2, 3, DPORT,
HDMI and TV jack.
Note: This speaker terminal is for 15W + 15W (8 ohm)
speaker.
Option board slot
Slot for board accessories. Please contact your supplier for
detailed information.