Hi there, I am encountering the same problem while trying to monitor whether an extension is on the phone or not. I am following up thus this topic. I am using Vodia PBX 5.3.2 with Cisco SPA525G phones. I have browsed several topics in the forum but still now, I am not able to get BLF working on my Cisco phones. Interestingly, I have seen that the PBX does not seem to allow SUBSCRIBE function from SPA525G. I have pasted below some of the SIP traces between the SPA525G and the PBX. REGISTER sip:pbx.DOMAINHIDDEN.com SIP/2.0 Via: SIP/2.0/UDP 192.168.1.24:5060;branch=z9hG4bK-43b24db From: "Alexandre" <sip:41@pbx.DOMAINHIDDEN.com>;tag=f8328d44a54068c2o2 To: "Alexandre" <sip:41@pbx.DOMAINHIDDEN.com> Call-ID: firstname.lastname@example.org CSeq: 35562 REGISTER Max-Forwards: 70 Authorization: Digest username="41",realm="pbx.DOMAINHIDDEN.com",nonce="c19519c7044e06a4f305f2a0644479d3",uri="sip:pbx.DOMAINHIDDEN.com",algorithm=MD5,response="cd1155a5883d396316b1ea1663dcde95" Contact: "Alexandre" <sip:email@example.com:5060>;expires=3600 User-Agent: Cisco/SPA525G-7.5.5 Content-Length: 0 Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER, UPDATE, MESSAGE Supported: replaces It appears from the above that SPA52G does not support SUBSCRIBE method to watch the status of an extension. In comparison with a SNOM 300 phone, I have seen a Subscribe registration in the SIP trace. Does Vodia PBX allow BLF reporting from the notify function? How could I manage to get the BLF feature working between Vodia PBX and Cisco SIP Phones? Thanks in advance, Alex.