How do I make Broadcom Corporation BCM43142 wifi card work with Netgear WNR614 N300 Wi-Fi Router on Ubuntu 16.04? The laptop is Dell Vostro 2520. Details of wireless card pasted at ubuntupastebin
Have you installed wl? This is the broadcom proprietary driver.
According to this link, your driver is supported by wl (broadcom sta driver) but not b43 (reverse engineered driver firmware extractor).
To activate wifi for your BCM43142:
sudo apt install bcmwl-kernel-source