dz.4

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)dz.4	8.1	9/11/90
.TH dz 4 VAX
.SH Name
dz \- DZ11/DZ32 communications interface
.SH Syntax
.B "device dz0 at uba0 csr 0160100 flags 0x????"
.br
.ti +0.5i
.B "vector dzrint dzxint"
.SH Description
.NXS "dz interface" "DZ11 communications interface"
.NXS "dz interface" "DZ32 communications interface"
.NXR "DZ11 communications interface"
.NXR "DZ32 communications interface"
A DZ11/DZ32 interface 
provides eight communication lines with partial modem control,
adequate for dialup use.
Each line attached to the DZ11/DZ32 communications interface
behaves as described in
.MS tty 4
and can be set to run at any of 16 speeds.  See
.MS tty 4
for the encoding.
.PP
Bit
.I i
of 
.PN flags 
cwcanmay be specified for a 
.PN dz 
to say that a line is not properly
connected, and that the line should be treated
as hardwired, with carrier always present.
Thus, specifying ``flags 0x04'' in the specification of 
.PN dz0
would cause line 2 to be treated in this way.
.PP
The 
.PN dz
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.
.SH Diagnostics
.B "dz%d: silo overflow"
.br
The 64-character input silo overflowed
before it could be serviced.  This can happen if a hard error occurs
when the CPU is running with elevated priority, as the system 
then prints a message on the console, with interrupts disabled.
.SH Files
.PN /dev/tty??
.TP 15
.PN /dev/ttyd?
(modem lines only)
.SH See Also
tty(4), MAKEDEV(8)