I've used BYOD Linksys PAP2 and PAP2T on this and other systems. They work great, but have the issue of TT talk-off. This is the generation of a touch-tone when triggered by a female voice. My wife's sister could be a Capt Crunch the way she would trip the talk-off. I switched to the Cisco SPA2102 an with the latest firmware does not have the talk-off problem. There is a selectable touch-tone delay in the config. The SPA2102 also has the built-in router, similar to the Ht502. That said, I keep the SPA2102 as a back-up and use a BYOD HT502 configured with VoIPo on port 1 and another provider on port 2. That was another lesson learned, don't put all your communication with one provider. In any case, the PAP2T is no longer supported with firmware upgrades and does not hold off on TT generation. I wouldn't use one.