Stalker LineShare for Mac

From CommuniGate Systems:

LineShare allows users to concurrently have several applications ie; Fax, ARA, BBS, Data, and Voice, use one serial port, one modem and one phone line. LineShare arbitrates and routes the incoming calls to the correct applications and directs outgoing calls to the user¹s modem thus eliminating the need for a dedicated line. LineShare creates virtual subports which are accessible to Macintosh Communications Toolbox.