Yealink SIP-T48G Administrator's Manual page 396

Administrator's Guide for SIP-T2_Series_T4_Series IP Phones
message. A GET request may contain variable named as "key" and variable value,
which are separated by "=". The valid URI format is: http(s)://phone IP
address/servlet?key=variable value.
The following table lists pre-defined variable values:
Variable Value
OK
ENTER
SPEAKER
F_TRANSFER
VOLUME_UP
VOLUME_DOWN
MUTE
F_HOLD
X
0-9/*/POUND
L1-LX
F1-F4
MSG
HEADSET
RD
UP/DOWN/LEFT/RIGHT
Reboot
AutoP
DNDOn
DNDOff
number=xxx&outgoing_uri=y
OFFHOOK
ONHOOK
ANSWER
382
Phone Action
Press the OK key.
Press the Enter soft key.
Press the Speakerphone key.
Transfers a call to another party.
Increase the volume.
Decrease the volume.
Mute a call.
Place an active call on hold.
Cancel actions or reject incoming calls or
mute or un-mute calls.
Press the keypad (0-9, * or #).
Press the line keys (for SIP-T48G, X=29, for
SIP-T46G/T29G, X=27, for SIP-T42G/T41P ,
X=15, for SIP-T27P , X=21, for SIP-T23P/G,
X=3, for SIP-T21(P) E2, X=2).
Press the soft keys.
Press the MESSAGE key.
Press the HEADSET key.
Press the RD key.
Press the navigation keys.
Reboot the phone.
Perform auto provisioning.
Activate the DND mode.
Deactivate the DND mode.
Place a call to xxx from SIP URI y.
Pick up the handset.
Hang up the handset.
Answer a call.