回复：Thanks, 出入自在，PAP2T is the replacement for SPA1001?

If you already have router, then SPA1001 or PAP2T both are good selection, PAP2T are the latest design for this perpose. SPA1001 has two line in and two lines out, but it make line 1 the default out line, so that you can use SipGate at line 2 as in, and without any settings you can automatically callout with a reasonable provider such as voipdiscount at line 1.

For PAP2T you have to make line forward from line 2 to line 1 then you can use this feature. I believe that PAP2T has more newer hardware than SPA1001. you can use Sipsorcery to switch from one provider to another and you also can use GooleVoice to save money from there.

By the way SPA3102 is also a good ATA, it has one line in but has 5 lines out, so that you can design your callout by different Voip Providers. With 出入's DDNS forward method you can have many lines call in either.
the router is not bad in SPA3102, you only need to use one DHCP server of all your routers.