Original text from OID Repository
SYNTAX Integer32
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"Address used to access this PDU via the external bus.
When MOD-BUS protocol is used the address is valid between 1-247.
When AP-BUS protocol is used the address is valid between 1-65535.
"
Sources for this description
Multiple manufacturers; see the original MIB MIB copies (LibreNMS/Observium Community)