Linksys PAP2
Voice Protocol: Session Initiation Protocol (SIP v2)
Voice Codecs: G.711 a-law, G.711μ-law, G.726, G.729 A, G.723.1
It is SIP 2.0 device. Therefore, it can works with 3CX PBX. Please go to PAP2 admin web page. Key in your the IPPBX IP, User ID and password for the extensions which configured for it.