I am active on the following Ham VOIP/SIP systems:
Echolink node KE4QCM 18456
Allstar node KE4QCM 60694
HamsOverIP: ext. 101230
AmateurWire: ext. 197796
NZSIP: ext. 61132
Extended Freedom Network: ext. 10448
FreeStar Everywhere: ext. 10038
https://www.elithecomputerguy.com/2010/08/voip-voice-over-ip-introduction/
https://www.elithecomputerguy.com/2012/10/overview-of-voip-and-voice-over-ip-concepts/
https://hamstat.com/ (Hams over IP)
https://dvnz.nz/welcome-to-nzsip/
https://extendedfreedom.network/index.php/connect/using-xfreedom-sip
https://freestar.network/everywhere/