SIP client supporrt
Instead of using real hardware (like a sound card or a winmodem), we'd like to be able to run linmodem as a SIP/RTP client (aka "softphone").
This way one can establish Modem calls via modern all-IP telephony. This obviously only works with aLaw/uLaw G.711 and not over any lossy codecs.
See X.150 through X.152 for ITU recommendations on modems over all-ip networks.