Originally Posted by UncleMike
Context: Wifi Near
Call [ Number:<number> AutoDial:Yes ]
Context: Wifi Connected [ SSID:<yourSSID> ]
Call [ Number:<CancelForward> AutoDial:Yes ]
This will forward calls when Tasker sees your Wifi network, and will cancel forwarding upon disconnect. This assumes that you're connecting to a network (you said you wanted to cancel upon disconnect). If it happens to see your network but is unable to connect for some reason, the forwarding will never get canceled.
Bweave, if you are connecting to the Wifi while at work, you only need one profile with an enter and exit task. So combine the two above.
But yeah, Mike, you are right, the question was when the phone "detects"...