iMac can’t see airport card and connect to WiFi
Earlier Mac models
Here you go: If you can't connect to a Wi-Fi network on Mac - Apple Support
As others already noted a Wi-Fi "card" is quite antiquated, and if your iMac is using one of them then it is very old. To identify your iMac model please read Identify your iMac model - Apple Support.
AirPort cards (7/1999 to 6/2004) = 802.11b (2.4 GHz, 11 Mbps).
AirPort Extreme cards (1/2003 to 1/2009) = 802.11b/g (2.4 GHz, up to 54 Mbps).
The original AirPort cards do not support AES encryption, but apparently are capable of connecting to an access point running WPA 1 and TKIP.
Are there airport cards that support WPA … - Apple Community
These days, if you were setting up a secure Wi-Fi network, the first thing you'd be told to do is to use WPA 2 or 3 and to require the use of AES encryption – disallowing WEP and TKIP.
What is an "airport card"?
An AirPort card is an Apple-brand Wi-Fi network interface card. Apple used to sell these separately for some PowerPC-based iMacs.
Ah ... in other words old and decrepit.
Airport card
