The most interesting aspect of the DSL-2750U J1 is not the official firmware, but what the community has done with it. Because the device uses a Broadcom chipset, it is compatible with custom firmware based on the Broadcom SDK.
Do not rely on memory or the box. Turn your router over and look at the physical sticker . Find the line that says "H/W Ver:".
Includes 1 RJ-11 ADSL port, 4 Fast Ethernet LAN ports, and a built-in 802.11b/g/n wireless interface.
Click "Browse" or "Choose File" and select the .bin firmware file you downloaded. Click or Update .