Tendzone TYCHO T 1212/CA - Manual (Page 40)

Figure 35
The module can only be used for device with telephone, and the device only provides a telephone interface. Therefore, it
is required to select "telephone input" in the input source.
Figure 36
The remote telephone signal will enter the selected input channel, and processing of the rest is the same with the analog
signal.
Meanwhile, it is also required to set the signal output to the remote end: select the channel required to be output to the
remote telephone, and select telephone output in the output setting of the channel: