If you need to check the power adapter of the device, this FAQ lists the power supply specification for phones:

Model	Power   Adapter
T19E2, T19PE2, T21E2, T21PE2,   T23G, T23P, T30, T30P, T31, T31G, T31P, T33G, T33P, T40G, T40P, W52P, W56P, W60B, W52H, W53H, W56H, W59R	AC 100~240V input and DC 5V/600mA output
T27G, T27P, T41S, T41U, T42G, T42S,   T42U, T43U, T53, T53W, W80B, W90B	AC 100~240V input and DC 5V/1.2A output
T29G, T46G, T46S,   T46U, T48G, T48S, T48U, T54W, T57W, T56A, T58A	AC 100~240V input and DC 5V/2A output
VP59, CP920, CP930W	AC 100~240V input and DC 12V/1A output
T49G	AC 100~240V input and DC 12V/2A output

Model	POE
T29G, T46G, T48G	Power over Ethernet (IEEE 802.3af), Class 0
T23G, T23P, W60B, W80B, W90B	Power over Ethernet (IEEE 802.3af), Class 1
T19PE2, T21PE2, T27P, T30P, T31G, T31P, T33G, T33P, T40G, T40P, T41S, T41U, T42G, T42S, T42U, T43U, T53, T53W, W52P, W56P	Power over Ethernet (IEEE 802.3af), Class 2
T27G, T46S, T46U, T48S, T48U, T54W, T57W, T56A, T58A, VP59, CP920, CP960	Power over Ethernet (IEEE 802.3af), Class 3

VP59 , T58A with Camera , SIP-T58A , SIP-T57W , SIP-T54W , SIP-T53W , SIP-T53 , SIP-T48S , SIP-T46S , SIP-T42S , SIP-T41S , SIP-T40G , SIP-T40P , SIP-T29G , SIP-T27G , SIP-T23G , SIP-T23P , SIP-T21(P) E2 , SIP-T19(P) E2 , SIP-T33P(G) , SIP-T31(P)(G) , SIP-T30(P) , W90 Multi-Cell System , W80 Multi-Cell System , W60P , W53P , W56P , W52P , T54W with DD10K , W41P , W59R , CP960 , CP930W-Base , CP920