Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/electronics/openSUSE_Tumbleweed/electronics.repo
zypper refresh
zypper install rdserialtool
Для 15.6 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/electronics/15.6/electronics.repo
zypper refresh
zypper install rdserialtool
Для 15.5 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/electronics/15.5/electronics.repo
zypper refresh
zypper install rdserialtool
Для 15.4 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/electronics/15.4/electronics.repo
zypper refresh
zypper install rdserialtool