How to reset default yealink ip phone series (SIP-T19P, SIP-T20P, SIP-T21P E2, SIP-T22P, SIP-T23P, SIP-T23G, SIP-T26P, SIP-T27P, SIP-T28P, SIP-T29G, SIP-T41P, SIP-T42G, SIP-T46G, SIP-T48G, SIP-T38G)

 

Nguồn: SIP Client