Abus AZWG10020 Installation And Operating Instructions Manual page 95

Connect the telephone cable to the screw terminals for the telephone cable
(TNV) on the PSTN module.
Pay attention to the correct assignment of A, B, A1, and B1.
A/B is the actual telephone connection; it goes to the "exchange", to the
private branch exchange, or to switching unit.
Other downstream external devices, such as telephones, answering
machines, or faxes, can be connected to A1/B1.
If the device establishes a connection, these external devices are
disconnected from the telephone line.
Please refer to the country-specific connections.
Germany
The easiest way to connect the device to the telephone network is
to use the included telephone cable. Connect the exposed wires
correctly to A/B and A1/B1. If you are unsure about what wire color
is assigned to a, b, a1, or b1,
use a suitable circuit tester.
Plug the TAE connector into a telephone socket of type N.
19 UK