SpanDSP is a library of DSP functions for telephony, in the 8000
sample per second world of E1s, T1s, and higher order PCM channels. It
contains low level functions, such as basic filters. It also contains
higher level functions, such as cadenced supervisory tone detection,
and a complete software FAX machine. The software has been designed to
avoid intellectual property issues, using mature techniques where all
relevant patents have expired. See the file DueDiligence for important
information about these intellectual property issues.
