1.Dd August 31, 2025 2.Dt COMCONTROL 8 3.Os 4.Sh NAME 5.Nm comcontrol 6.Nd control a special tty device 7.Sh DEPRECATION NOTICE 8The 9.Nm 10utility is deprecated and will be removed in 11.Fx 16.0 . 12.Sh SYNOPSIS 13.Nm 14.Ar special_device 15.Op drainwait Ar number 16.Sh DESCRIPTION 17The 18.Nm 19utility is used to examine and modify some of the special characteristics 20of the specified tty device. 21If no arguments other than the device (or "-" for stdin) 22are specified, 23it prints the settings of all controllable characteristics. 24This usage requires only read access on the device. 25Only the superuser can change the settings. 26.Pp 27The following options are available: 28.Bl -tag -width indent 29.It Cm drainwait Ar number 30Set the time to wait for output drain 31to the given number. 32The units are seconds. 33The default is 5 minutes, 0 means 34waiting forever. 35This option is needed mainly to specify an upper limit of minutes 36to prevent modem hanging. 37.El 38.Pp 39The standard way to use 40.Nm 41is to put invocations of it in the 42.Pa /etc/rc.d/serial 43startup script. 44.Sh FILES 45.Bl -tag -width /dev/ttyd? -compact 46.It Pa /dev/ttyd? 47dialin devices, hardwired terminals 48.It Pa /dev/cuau? 49dialout devices 50.El 51.Sh SEE ALSO 52.Xr stty 1 53.Sh HISTORY 54Originally part of cgd's com package patches, version 0.2.1, to 55.Bx 386 0.1 . 56Once controlled bidirectional capabilities. 57Little is left to control now that these capabilities are standard. 58.Sh AUTHORS 59.An Christopher G. Demetriou 60