For openSUSE Leap 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:vicidial:sandbox/openSUSE_Leap_15.6/home:vicidial:sandbox.repo
zypper refresh
zypper install dahdi-tools
For openSUSE Leap 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:vicidial:sandbox/openSUSE_Leap_15.5/home:vicidial:sandbox.repo
zypper refresh
zypper install dahdi-tools
For openSUSE Leap 15.3 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:vicidial:sandbox/openSUSE_Leap_15.3/home:vicidial:sandbox.repo
zypper refresh
zypper install dahdi-tools