Algo 2507 ring detector, enable loud ringing, notification and visual alerting directly from a compatible VoIP telephone without a SIP registration (ideal for MS Teams environments). Technical Note: Algo devices must be on firmware 4.1 or above. Compatible VoIP telephones, Poly VVX series and CCX series, Yealink T55A, T56A, T58A, MP54, MP56, MP58.