What this means
The IEEE assigned the MA-S block 70B3D58D9 to MB connect line GmbH Fernwartungssysteme. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting 70:B3:D5:8D:9, it is MB connect line GmbH Fernwartungssysteme hardware.