Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

Chapter 8 219
Intrinsics Reference
FDEVICECONTROL
If issued against a terminal connected via DTC Telnet
or via VT to an HP-UX or PC local client, this call will
return an error.
63 Single echo typeahead mode.
This directive specifies that the device driver shall
withhold the echoing of typeahead data until a read is
posted for the data. This facility prevents passwords
and other data from being echoed at inappropriate
times. This directive is not valid if typeahead mode is
disabled. A buffer value of 1 enables single echo
typeahead mode. A buffer value of 0 restores normal
typeahead mode.
If issued against a terminal connected via PAD or DTC
Telnet, this call will return a CCE condition code, but
the device control action will not occur. If issued against
a terminal connected via VT to an MPE V local client,
this call will return an error. Also, this directive is
supported for VT connections to an MPE/iX host or PC
running appropriate software only.
64 Ignore parity error on input mode.
This directive causes the device driver to ignore parity
errors on input data. If buffer is 1, the device driver
ignores parity errors on data received from the
terminal. If buffer is 0, the device driver reports all
parity errors; this is the default setting.
If this directive is issued against a terminal connected
via PAD, DTC Telnet, or Telnet/iX, this call will return
a CCE condition code, but the device control action will
not occur. This directive is not supported for use with
VT connections and will return an error if used
65 Inter-byte timer.
This directive sets the inter-byte timer. When a read is
posted with the inter-byte timer enabled, the DTC
waits indefinitely to receive the first character of data.
The inter-byte timer starts when the DTC receives a
character from the terminal. The DTC restarts the
timer each time it receives another character. If the
timer reaches the specified duration before the DTC
receives the next character, the read completes. If
typeahead mode is enabled, the timer does not start
until all data has been read from the typeahead buffer.
The inter-byte timer and the read timer are
independent of one another and either may complete a
given read.