Convert Wireless ADSL Modem Router into a Wireless Access Point, possible?

I have a old "ADSL 4-port wireless modem router" laying around and I wondering could I convert it into WLAN Access Point. Is is possible for Wireless router unit with built-in modem? so far I not able to find much information on web.

My model is TP-Link TD-W8961ND

Yes. Simply disable NAT and DHCP service. You want it to be just a bridge, with wireless AP mode on.

Use one of the LAN Ethernet ports to connect it into your home LAN (e.g. into a LAN port of your upstream router).

Here is the official link from tp-link http://www.tp-link.in/faq-417.html

Step 1

Connect your computer to a second LAN port on your TP-Link N router using an Ethernet cable.* Login to the TP-Link web interface through the IP address listed on the label on the bottom of your TP-Link N router (see below link for assistance):

How do I log into the web-based utility of a TP-Link router

Note: Though possible, it is not recommended to attempt this process over Wi-Fi

Step 2

Go to Network>LAN on the side menu and change the LAN IP address of your TP-Link N router to an IP address on the same segment of the main router. This IP address should be outside the main router’s DHCP range.

Example: if the DHCP of your main router is 192.168.2.100 – 192.168.2.199 then you can set the IP of the TP-Link N router to 192.168.2.11

Note: After changing the LAN IP address a reboot will be required and you will need to log into the TP-Link N router with the new IP address.

Step 3

Go to Wireless>Wireless Settings and configure the SSID (Network name)which can be the same or different from the main router’s. Select Save.

Step 4

Go to Wireless>Wireless Security and configure the wireless security. WPA/WPA2-Personal is recommended as the most secure option. Once configured, click Save.

Note: If using a dual band router, repeat this process for the 5GHz band as well.

Step 5

Go to DHCP>DHCP Settings and select Disable the DHCP Server. Select Save.

Step 6

Go to System Tools>Reboot and select Reboot to reboot the device.

Step 7

Use an Ethernet cable to connect the main router to your TP-Link N router through their LAN ports (any LAN ports may be used). All other LAN ports on your TP-Link N router will now grant devices Internet access. Alternatively, any Wi-Fi device can now access the Internet through your TP-Link N router by using the SSID and Password set up in the above steps.