2 V.21 Modem for ISDN4BSD.
6 The modem is implemented in software and is rather simple minded.
8 It works with my Telebit TB2500 and Zyxel 2864I modems.
10 There are plenty of knobs and handles which can be adjusted and I have
11 no real idea what to set them to for best all-round performance.
13 The carrier detect timer may be a bit short tempered, and this is
14 probably why the dialing modem needs to be told to talk V.21 up
15 front. If this code were mode tolerant of loss of carrier auto
16 negotiation might work.
18 When you get carrier ("CONNECT 300"), you must press a key before the
19 login banner gets printed. See the comments in "input_byte" why this
24 Implementes a crude "send these tones" facility, but it is enough to
25 take most of the real-time worries out of doing FSK modulation in
26 software. If suitably extended, the code could also be used to
27 send DTMF tones and other similar signals.
31 The program is started from /etc/isdn/isdnd.rc:
39 local-phone-incoming = 2934812934
40 remote-phone-incoming = *
41 dialin-reaction = answer
47 Poul-Henning (phk@freebsd.org)
50 $FreeBSD: src/share/examples/isdn/v21/README,v 1.1.2.1 2001/08/10 14:59:48 obrien Exp $
51 $DragonFly: src/share/examples/isdn/v21/README,v 1.2 2003/06/17 04:36:57 dillon Exp $