No Wireless interface - Beetel 450tc1 Adsl+2 Modem

[NetUser_Online]

Hi...

I am trying to configure wifi on my modem - Beetel 450tc1 ADSL+2 Modem, but, there is no 'Wireless' tab in 'Interface Setup'.
The modem was given by Airtel BB and earlier, wifi was working. And, now, I am trying to configure wifi access with BSNL BB but, wireless interface is missing. I have also upgraded/downgraded the firmware, but, there is no improvement.

KIndly guide/help.

Thanks!