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authorphk <phk@FreeBSD.org>2005-01-27 09:29:52 +0000
committerphk <phk@FreeBSD.org>2005-01-27 09:29:52 +0000
commitc867c148a586bb5a1d4a31ac25d67355d9adb667 (patch)
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parent0eadcea76bfc03eb957de15b1074a24cb89db33b (diff)
downloadFreeBSD-src-c867c148a586bb5a1d4a31ac25d67355d9adb667.zip
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Update the information, (and likely break all formatting rules).
Diffstat (limited to 'share/man/man4/nmdm.4')
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1 files changed, 20 insertions, 15 deletions
diff --git a/share/man/man4/nmdm.4 b/share/man/man4/nmdm.4
index 1fcc17b..f811d6e 100644
--- a/share/man/man4/nmdm.4
+++ b/share/man/man4/nmdm.4
@@ -32,23 +32,21 @@
.Sh DESCRIPTION
The
.Nm
-driver provides support for a device-pair termed a
-.Em null modem pair .
-A null modem pair is a pair of character devices.
-Each device provides to a process an interface identical
-to that described in
-.Xr tty 4 .
-However, whereas most other devices which provide the
-interface described in
+driver provides two
.Xr tty 4
-have a hardware device of some sort behind them, the
+devices connected
+by a virtual "null modem" cable.
+.Pp
+If either of the two tty devices have the CDSR_OFLOW bit
+("stty dsrflow")
+set in their line discipline, the
.Nm
-device has, instead, another process manipulating
-it through the other half of the pair.
-That is, anything written on the first device is
-given to the second device as input and anything written
-on the second device is presented as input on the first
-device.
+device will emulate the speed configured in the
+.Xr termios 4
+settings.
+The speed emulation works independently in the two directions,
+controlled by the slower ends termios settings (c_ispeed, c_ospeed,
+CS5...CS8, CSTOPB and PARENB).
.Sh FILES
.Bl -tag -width /dev/nmdm[N][AB] -compact
.It Pa /dev/nmdm Ns Ar N Ns Op Pa AB
@@ -59,9 +57,16 @@ node has a matching
.Pa B
node.
.El
+.Pp
+The
+.Nm
+driver implements "on-demand device creation" so simply accessing a
+given instance in /dev will create it.
.Sh DIAGNOSTICS
None.
.Sh SEE ALSO
+.Xr stty 1 ,
+.Xr termios 4 ,
.Xr tty 4
.Sh HISTORY
The
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