You definitely want to consider the Linksys WRP400 Wireless-G Broadband Router with 2 Phone Ports and QoS (suggest good T.38 support but need to be tested). Few installations with this device on a business class Internet connetion for dedicated VoIP network, so far and it delivers! Around 140$CAD but I found interesting deal lately, you surely get it fot cheaper.

Linksys WRP400 Wireless router with 3 phone ports
http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&cid=1175238289895&pagename=Linksys%2FCommon%2FVisitorWrapper

NothinElse

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VoiceMeUP - VoIP Trunking
http://www.voicemeup.com

If you actual router is still working fine and you're happy with it, just pick up a cheap ATA (Grandstream, Linksys) for $50 or less and plug it in to replace your old 486. I'm not sure it's worth spending $100+ to replace both boxes when you already have something working.

Maan

My Grandstream 486 just died. So I'm in the market. Current router is Netgear MR814v2, which does NAT, WiFi, and I had the 486 hooked to it, and things worked.

Is it better to go with a single box that does everything? Or a different/better router with QoS support? Or?