install asterisk 21 on redhat 9 script
REF: https://docs.rockylinux.org/guides/communications/asterisk_installation/ https://www.redhat.com/sysadmin/topics/voip https://github.com/redhat-nfvpe/vnf-asterisk https://docs.asterisk.org/Getting-Started/Installing-Asterisk/Installing-Asterisk-From-Source/What-to-Download/ https://computingforgeeks.com/how-to-install-asterisk-16-lts-on-centos-rhel-8/
https://www.carotechnology.com/howto/asterisk.html https://www.h323plus.org/