Install libspandsp-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libspandsp-doc
Description:
Documentation for the spandsp signal processing library
a low-level signal processing library that modulates and demodulates signals commonly used in telephony, such as the "noise" generated by a fax modem or DTMF touchpad. . This package contains the online API in HTML.
Homepage: http://www.soft-switch.org/
Version: 0.0.6+dfsg-0.1
Section: universe/doc