dfa.4

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)dfa.4	2.1	3/10/87
.TH dfa 4 VAX
.SH Name
dfa \- DFA01 communications interface
.SH Syntax
.B "device dz0 at uba0 csr 0160100 flags 0x0 vector dzrint dzxint
.NXS "dfa interface" "DFA01 communications interface"
.NXR "DFA01 communications interface" 
.NXA "DZQ11 communications interface" "DFA01 communications interface"
.SH Description
The DFA01 contains two DF224-compatible modems with a DZQ11-compatible
interface.
Each line attached to the DFA01
behaves as described in
.MS tty 4 .
See 
.MS tty 4
for the encoding.
Lines may operate at 300, 1200, or 2400 baud.
.NT Caution
The DZQ11 interface is capable of baud rates up to 9600 baud,
but, because the modem is restricted to speeds of 300, 1200, and 2400 baud, 
all other baud rates are considered illegal and pass meaningless data.
.NE
.PP
A flags field of 0x0 must be specified to indicate that the lines are
to be treated as modems.
.PP
An 
.MS acucap 5
entry of \f(CWdfa01\fP should be used to describe the 2400 baud
autodial attributes used by such programs as 
.MS tip 1c ,
.PN cu
and
.MS uucp 1c .
.NXR "DFA01 communications interface" "acucap file entry"
For pulse tone dialing at 2400 baud, an 
.MS acucap 5
entry of \f(CWdfa01-p\fP should be used.
To dial at 1200 baud, the \f(CWdfa01-1200\fP or \f(CWdfa01-1200p\fP (pulse dial)
should be used.
To use the DFA01 autodialer, the terminal line must be set to
no parity.  
.PP
Any entry in the
.MS remote 5
file that specifies an 
ACU type of \f(CWdfa01\fP must specify no parity.  The
following example shows how a correct entry in the
.MS remote 5
file may look:
.NXR(e) "DFA01 communications interface" "remote file entry"
.EX
dial2400|2400 Baud attributes:\e
	:dv=/dev/ttyd0:br#2400:at=dfa01:du:pa=none:
.EE
.PP
The 
.PN dfa 
driver normally uses its input silos
and polls for input at each clock tick (10 milliseconds)
rather than taking an interrupt on each input character.
.PP
.MS MAKEDEV 8
will produce four terminal lines for the DZQ11 interface.
The second and fourth lines are the actual modem lines.  
The first and third lines
pass status information when the modem is on line.  
.SH Diagnostics
.PP
\fBdz%d: receive fifo overflow\fR.  
.br
The character input fifo overflowed
before it could be serviced.
This can happen if other devices heavily utilize the bus
and CPU, preventing interrupts from the DFA01 from being serviced.
This may cause a few input characters to be lost to users.
It is not serious.
.SH Files
.TP 15
.PN /dev/tty??
.TP
.PN /dev/ttyd?
Dialups
.SH See Also
tty(4), acucap(5), MAKEDEV(8)