Install libosmotrau1 by entering the following commands in the terminal:
sudo apt update sudo apt install libosmotrau1
GSM trau handling
This library implements the Transcoder and Rate Adaptation Unit (TRAU) for GSM systems. It is closely related to the libosmo-abis library. . TRAU performs transcoding function for speech channels and rate adaptation (RA) for data channels in the GSM network.