Yealink SIP-T54S Administrator's Manual page 844

Administrator's Guide for SIP-T2 Series/T19(P) E2/T4 Series/T5 Series/CP860/CP920 IP Phones
The action string 1013$Tinvite$$Cwc$$Cp10$$Penter number&C4&N$$Tdtmf$$Cp3$$Chu$ is
executed in order as follows:
A prompt appears on the LCD screen.
1)
Enter a number for up to 4 digits. For example, 1234. Press the OK soft key to continue.
2)
The IP phone places a call to 1013 using the default account, and then waits for
3)
connection.
After connection, there is a 10 second pause, and then the entered number 1234 is using
4)
DTMF dialing on the active call.
After sending DTMF digits, there is a 3 second pause, and then the active call is
5)
automatically disconnected.
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