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1.1 root 1: .\" Copyright (c) 1990 The Regents of the University of California.
2: .\" All rights reserved.
3: .\"
4: .\" This code is derived from software contributed to Berkeley by
5: .\" the Systems Programming Group of the University of Utah Computer
6: .\" Science Department.
7: .\"
8: .\" Redistribution and use in source and binary forms are permitted provided
9: .\" that: (1) source distributions retain this entire copyright notice and
10: .\" comment, and (2) distributions including binaries display the following
11: .\" acknowledgement: ``This product includes software developed by the
12: .\" University of California, Berkeley and its contributors'' in the
13: .\" documentation or other materials provided with the distribution and in
14: .\" all advertising materials mentioning features or use of this software.
15: .\" Neither the name of the University nor the names of its contributors may
16: .\" be used to endorse or promote products derived from this software without
17: .\" specific prior written permission.
18: .\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
19: .\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
20: .\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21: .\"
22: .\" @(#)dcm.4 5.1 (Berkeley) 6/29/90
23: .\"
24: .TH DCM 4 "June 29, 1990"
25: .UC 7
26: .SH NAME
27: dcm \- HP 98642A communications multiplexer
28: .SH SYNOPSIS
29: .B "device dcm0 at scode? flags 0xe"
30: .SH DESCRIPTION
31: The 98642A is a four port EIA RS-232C (CCITT V.28) communications
32: multiplexer. The 98642A has three direct-connect ports and one port with
33: full modem control.
34: .PP
35: Each line attached to the 98642A behaves as described in
36: .IR tty (4).
37: Input and output for each line may set to one of following baud rates;
38: 50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800,
39: 9600, 19200, 38400. See
40: .IR tty (4)
41: for the encoding.
42: .PP
43: Flags is usually specified as 0xe since 3 of the 4 ports (1-3) do not support
44: modem control and should be treated as hard-wired with carrier always present.
45: If port 0 does not have the need for modem control then flags can be specified
46: as 0xf.
47: .PP
48: Each port on the 98642A has a 128 byte input silo and a 16 byte output silo.
49: Interrupts happen on a per character basis unless the interrupt
50: rate for the card reaches 70 interrupts per second at which time the
51: driver changes to a 16.7ms (60 interrupts per second) polling scheme until
52: the interrupt rate drops.
53: .SH FILES
54: /dev/tty0[0-9a-f]
55: .SH "SEE ALSO"
56: tty(4)
57: .SH DIAGNOSTICS
58: \fBdcm%d port%d: silo overflow\fR Input Silo has overflowed and incoming data
59: has been lost.
60: .PP
61: \fBdcm%d port%d: uart overflow\fR The 3 character buffer in the uart has
62: overflowed.
63: .SH BUGS
64: Total throughput per card, all ports together, is limited to 76800 bits per
65: second continuous input rate.
66:
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