El Cid is a caller ID program for Linux. It just sits on your modem waiting for something to happen, parses the input, and displays the caller ID information. All records are logged to a file in csv format so you can easily parse it for logging into a database, viewing on the Web via CGI, etc.
capircvd is a voice/fax gateway. It receives fax (G3) and voice-calls using an ISDN-Bus, an AVM ISDN-Card (active or passive) and CAPI20 from isdn4linux, or AVM. It can be used on either P2P (with DDI) or P2M S0-bus. After reception, it can process files (send as mail) using an external handler (included).