J139 use INVITE instead of REGISTER

[george36]

I would like to use a couple of my J139 to test a SIP server and need to change them to use INVITE instead of REGISTER. I only care about making outgoing calls and don't need any presence or incoming calls to phone.


The phones are J139D01A with firmware 4.0.7.1.5 running Open SIP. Is this possible?


On an older phone from a different manufacturer I used to use, I could change the REGISTER time to 0 and the phone would use INVITE.


Thanks,
David


I should add to this. Due to the REGISTER request the phone is at "Acquiring Service..." So I can't just try making a call from the phone.