Hi All, I have an ATA 186 (http://www.cisco.com/warp/public/cc/pd/as/180/186/prodlit/at186_ds.pdf) telephone adapter behind ISA. I can not get it to work. It works fine behind NetGear wireless router. The ATA 186 is provided by Vonage. They say it won't work behind ISA. Any ideas? Thanks, - Robert