The pseudoterminal inherits its device characteristics
from the system default parameters, with the following exceptions:
The device inherits initial
device characteristics from the SYSGEN-supplied default values. You
can modify the device characteristics during device creation by supplying
new characteristics.
The HOSTSYNC terminal
characteristic is always set.
The device is set to NOMODEM
and cannot be set to MODEM.
The device is set not
to time output character transmission. Hardware controllers time output
character transmission to determine whether the controller is broken.
You can obtain information on pseudoterminal characteristics
by using the Get Device/Volume Information ($GETDVI) system service,
as described in “Terminal Driver Device Information” and the HP OpenVMS System Services Reference
Manual.
Applications should assign a channel other than
the control channel to read data from, write data to, read, or alter
the pseudoterminal characteristics. An attempt to perform such I/O
with the control channel, or any other attempt to queue an illegal
or unsafe I/O request, results in an SS$_CHANINTLK error.
