ZMD405CT44 is an electricity meter from the international manufacturer Landis+Gyr. Under the front cover of the electricity meter, there is a shaft for connecting a plug-in module that complements the communication interfaces.

Figure 4 - ZMD405CT44 with and without covers

Figure 5 - ZMD405CT44 communication interfaces

On the Figure 5, the main elements on the terminal board of the electricity meter and its communication interfaces are marked:

1. 1. Terminal box for the electrical network. The tested model used semi-direct current measurement and did not have a connected measuring loop, only reading voltage.
   2. RS485 serial bus. It is connected to an RJ-12 connector. By default, it is in "master" mode - it does not wait for incoming commands but forwards incoming communication from the ethernet interface to the serial bus.
   3. RJ-45 Ethernet.
   4. Optical interface for attaching an optical head.

Landis+Gyr MAP120 utility software

The MAP120 utility software was supplied with the electricity meter, which can be used to configure the electricity meter settings, but not to read the values of common registers.
The tested electricity meter had a fixed IP address, and to communicate with it, it was practical to set up 2 IP addresses on one interface on our computer - one for Internet access and one for communication with the electricity meter. However, the MAP120 software could not use the IP interface with two IP addresses. Only one IP address had to be set on the interface. It was also not possible to set the parameters for communication via the optical head, and due to the RS485 master mode, this interface could not be used either.

Figure 6 - Sample from the Landis+Gyr MAP120 application
The MAP120 application contains detailed user documentation, accessible via the F1 key, in which individual configuration parameters of the electricity meter are described.

Parameters for DLMS communication

The electricity meter uses HDLC on the relational layer.

• HDLC physical address = calculated from the bottom 4 digits of the serial number + 1000
• HDLC logical address = 1 (0x01)
• HDLC client address = 16 (0x10) for unauthorized access without password, 32 (0x20) with password
• Heslo = 00000000