Administrator’s Guide for SIP-T2xP IP Phones152server. IP phones themselves do not have memory to store the recording, what theycan do is to trigger the recording and indicate the recording status.Normally, there are 2 main methods to trigger a recording on a certain server. We callthem record and URL record. Record is for the IP phone to send the server a SIP INFOmessage containing a specific header. URL record is for the IP phone to send an HTTPGET message containing a specific URL to the server. The server processes thesemessages and decides to start or stop a recording.RecordWhen a user presses a record key for the first time during a call, the IP phone sends a SIPINFO message to the server with the specific header “Record: on”, and then therecording starts.Example of a SIP INFO message:Via: SIP/2.0/UDP 10.1.4.148:5063;branch=z9hG4bK1139980711From: "827" 827@192.168.1.199>;tag=2066430997To:<sip:614@192.168.1.199>;tag=371745247Call-ID: 1895019940@10.1.4.148CSeq: 2 INFOContact: 827@10.1.4.148:5063>Max-Forwards: 70User-Agent: Yealink SIP-T28P 2.71.0.140Record: onContent-Length: 0When the user presses the record key for the second time, the IP phone sends a SIPINFO message to the server with the specific header “Record: off”, and then therecording stops.Example of a SIP INFO message:Via: SIP/2.0/UDP 10.1.4.148:5063;branch=z9hG4bK1619489730From: "827" 827@192.168.1.199>;tag=1831694891To:614@192.168.1.199>;tag=2228378244Call-ID: 1051886688@10.1.4.148CSeq: 3 INFOContact: 827@10.1.4.148:5063>Max-Forwards: 70User-Agent: Yealink SIP-T28P 2.71.0.140Record: offContent-Length: 0URL RecordWhen a user presses a URL record key for the first time during a call, the IP phone sendsan HTTP GET message to the server.
