51 lines
1.5 KiB
Plaintext
51 lines
1.5 KiB
Plaintext
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V.21 Modem for ISDN4BSD.
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INTRODUCTION:
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The modem is implemented in software and is rather simple minded.
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It works with my Telebit TB2500 and Zyxel 2864I modems.
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There are plenty of knobs and handles which can be adjusted and I have
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no real idea what to set them to for best all-round performance.
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The carrier detect timer may be a bit short tempered, and this is
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probably why the dialing modem needs to be told to talk V.21 up
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front. If this code were mode tolerant of loss of carrier auto
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negotiation might work.
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When you get carrier ("CONNECT 300"), you must press a key before the
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login banner gets printed. See the comments in "input_byte" why this
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is.
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THE KERNEL PART:
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Implementes a crude "send these tones" facility, but it is enough to
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take most of the real-time worries out of doing FSK modulation in
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software. If suitably extended, the code could also be used to
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send DTMF tones and other similar signals.
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INSTALLATION:
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The program is started from /etc/isdn/isdnd.rc:
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entry
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name = I4BTEL
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usrdevicename = tel
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usrdeviceunit = 0
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isdncontroller = 0
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isdnchannel = -1
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local-phone-incoming = 2934812934
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remote-phone-incoming = *
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dialin-reaction = answer
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answerprog = v21modem
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b1protocol = raw
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idletime-incoming = 5
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Poul-Henning (phk@freebsd.org)
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19991212
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$FreeBSD$
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