Asus RT-N56U router connectity to TP-Link TD8616

[#1]

Hi,
I got the Asus router as a gift, and decided to buy the modem to enable it to connect to plusnet broadband, as it seemed a good combination, from reviews. I setup the modem according to old Linksys WAG325N PPPoA settings in bridge mode. The ADSL light is on, and diagnostics seem to indicate it's getting good connectivity.  Looked at the modem instructions, and said and setup client in PPPOE, connect cable from modem cat 5 port to WAN port on router. Left router default operation in IP sharing modem and tried to setup PPPOE connection. But for some reason it's connecting to it.
The modem has a static IP address. In the PPPOE settings do I need to specify in WAN addresses, the IP address of the router, or do I leave blank. I doesn't detect the router from the main page. I tried various ethernet cables. When I try and set the gateway address in PPPOE of 192.168.1.1 (the ip address of modem), router says not allowed.  Any ideas.
Thanks.

[#2]

The 8616 is purely a modem and so you should set the Asus for pppoe as its WAN connection. Looking at the 8616 manual, however, it does seem to have a LAN ip allocated to it. I guess this is purely to access its WEB GUI. At the default of 192.168.1.1 this is going to clash with the ASUS and is probably what is causing your problems. Set this IP to 192.168.1.2 and then change the DHCP pool on the ASUS to start from 192.168.1.10.
Hope that helps.

[#3]

@MisterW,
Thank's for the reply. That exactly what I found. Thought about changing the modem's IP address at the time, but couldn't find anything in the docs. I'll take another look.
I
regards
Bob

[#4]

According to the manual I downloaded ( for a TD-8616_V7 ) its on page 16.