This is a distinction arising from the integration of SER and Kamailio into sip-router. Selects come from the SER side, while PVs come from the Kamailio side. You can use either one depending on your needs; there is no methodological prescription here, want one though you may. :-) Beware that the @... syntax for accessing selects is not recognised/evaluated inline to a string literal by most functions that take PVs in their arguments, though, so you'd have to wrap the select inside the PV container for accessing them: $sel(...) Obviously, there are things selects provide that lack corresponding PVs, such as much more granular SIP message attributes, access to global cfg_get variables, etc. But in terms of it being better to use one or the other, or the theory that one is somehow deprecated at the expense of the other -- that is not the case. -- This message was painstakingly thumbed out on my mobile, so apologies for brevity, errors, and general sloppiness. Alex Balashov - Principal Evariste Systems LLC 260 Peachtree Street NW Suite 2200 Atlanta, GA 30303 Tel: +1-678-954-0670 Fax: +1-404-961-1892 Web: http://www.evaristesys.com/ On Jan 28, 2012, at 3:16 AM, Spencer Thomason <spencer(a)5ninesolutions.com> wrote: