dcl.4

早期freebsd实现

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.\"     @(#)dcl.4	8.1 (Berkeley) 6/9/93
.\"
.Dd June 9, 1993
.Dt DCL 4 hp300
.Os
.Sh NAME
.Nm dcl
.Nd
.Tn HP
98628A communications link
.Sh SYNOPSIS
.Cd "device dcl0 at scode? flags 0x1"
.Sh DESCRIPTION
The 98628A is a buffered
.Tn EIA
.Tn RS-232C
.Pf ( Tn CCITT
.Tn V.28 )
communications interface.
It has one port with full modem control.
.Pp
Input and output for each line may set to one of following baud rates;
0, 50, 75, 110, 134.5, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
9600, 19200.
.Pp
An optional argument
.Ar flags
may be set to 1 if the line should be treated as hard-wired with
carrier always present, or to 0 if modem control is desired.
.Pp
Use
.Tn HP
cable "98626 & 98628 opts.002,
.Tn RS232-C
.Tn DCE CABLE ,
5061-4216" to attach non-modem devices.
Use
.Tn HP
cable "98626 & 98628 opts.001,
.Tn RS232-C
.Tn DTE CABLE ,
5061-4215" to attach modems.
.Pp
The 98628A has a 256 byte input silo and a 256 output silo. Input interrupts
happen on a per character basis.
.Pp
The high water and low water marks in the kernel tty routines are completely
inappropriate for a device like this with a large input buffer.  Don't use
tandem mode if possible.  A fast system can handle input at 19.2K baud without
receive overflow.
.Pp
For output to devices that make heavy use of
.Tn XON/XOFF
a write size of less
then 256 will improve performance marginally.
.Sh FILES
.Bl -tag -width /dev/ttyl[0-9] -compact
.It Pa /dev/ttyl[0-9]
.El
.Sh DIAGNOSTICS
.Bl -diag
.It dcl%d: error 0x%x RESET CARD.
Where the errors are encoded:
.Bd -unfilled -offset indent
0x06 card failure
0x0d uart receive overflow
0x0e receive overflow
0x0f missing external clock
0x10 cts false too long
0x11 lost carrier
0x12 activity timeout
0x13 connection not established
0x19 illegal databits/parity
0x1a register address out of range
0x1b register value out of range
0x-- unknown error
.Ed
.El
.Sh SEE ALSO
.Xr tty 4
.Sh BUGS
Breaks received at a faster rate then 1 break every second will be 
recognized as a single break.
.Pp
Console use is not supported.
.Pp
The
.Tn RS-422/423/499 ,
.Tn MTS-DSN/DL
modes of the card are not supported.