Yealink SIP-T38G, Administrator'S Manual

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Configuring Advanced Features
143
5. Enter the period time in the MWI Subscription Period (Scope: 0~84600) (seconds)
field.
6. Click Confirm to accept the change.
Call recording enables a user to record a call. It depends on support from a SIP server.
When the user presses a call record key, the IP phone sends a record request to the
server. The IP phones themselves do not have memory to store the recording, what they
can do is only to trigger the recording and indicate the recording status.
Normally, there are 2 main methods to trigger a recording on a certain server. We call
them record and URL record. Record is for the IP phone to send the server a SIP INFO
message containing a specific header. URL record is for the IP phone to send an HTTP
URL to the server. The server processes these messages and decides to start or stop a
recording.
Record
When a user presses a record key for the first time during a call, the IP phone sends a
SIP INFO message to the server with a specific header ―Record: on‖, and then the
recording starts.
The example of a SIP INFO message for reference:
Via: SIP/2.0/UDP 10.1.4.148:5063;branch=z9hG4bK1139980711
From: "827" <sip:827@192.168.1.199>;tag=2066430997