these are my first ports, so they are most likely not perfect.
# cat spandsp/pkg/DESCR
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
functions, such as basic filters. It also contains higher level functions,
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
# cat callweaver/pkg/DESCR
CallWeaver is a community-driven vendor-independent
cross-platform open source PBX software project
(formerly known as OpenPBX.org). It was originally
derived from Asterisk. Now it supports analog and
digital PSTN telephony, multi-protocol voice over IP
telephony, fax, software-fax, T.38 fax over IP and
many telephony applications such as IVR, conferencing
and callcenter queue management.