Apple Power Macintosh 4400 - Manual (Page 158)

If the card does not have a hook, simply pass the external connector through
the opening in the vertical plate as shown. (Some cards have an external
connector that protrudes through the opening; others, like the one shown
here, have a flatter external connector.)
6 Passing the external connector through the opening in the vertical plate, insert the
card into the communication slot. Press down on the card until the connector is solidly
in place.
Don’t force the card. If you meet resistance, pull it out and try again.
7 To see if the card is properly connected, lift it gently. If it resists and stays in place,
it’s connected.
Communication card slot
Communication card
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