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

136 Chapter7
Programming for PAD, DTC Telnet, Telnet/iX Server, and VT Devices
PAD Access to MPE/iX Systems
There are, however, a number of differences in the way device control
functions operate over PAD connections. The individual differences in
the operation of each FCONTROL and FDEVICECONTROL call are
documented in the Intrinsics Reference chapter of this manual. The
following summary is provided here for your convenience.
FCONTROL
Some FCONTROLs are ignored by PAD. These are calls that attempt to
control some function that is not supported over PAD, such as changing
terminal speed or setting parity. These calls will return a CCE
condition code, but no device control action will take place. Any values
returned in these calls may not be a true reflection of device control
settings. These FCONTROLs include:
• FCONTROL(10), set line speed.
• FCONTROL(11), set line speed
• FCONTROL(23), disable parity checking.
• FCONTROL(24), enable parity checking.
• FCONTROL(34), allow printing of
[CTRL]X echo.
• FCONTROL(35), disable printing of
[CTRL]X echo.
• FCONTROL(36), define parity setting.
• FCONTROL(40), determine current speed.
Reads following a call to FCONTROL(27), which enables binary mode,
return a CCL condition code with the file system error FSERR20
(INVALID OPERATION), until binary mode is disabled
(FCONTROL(26) ), if you are using a version prior to release 4.5.
Calls to FCONTROL(37), to set both terminal type and speed, will
change the terminal type setting, but will have no impact on how the
device actually operates. A CCE condition code will be returned. (Note
that this is a difference from how PAD devices behave on MPE V
systems.)
Some caution should be taken when using FCONTROL(4), which sets a
timeout interval for a read. Keep in mind that some delays may be
caused by the network over which the PAD is transmitting. In such
cases you may want to add some time to the timeout value you would
normally specify for the call.
FDEVICECONTROL
The FDEVICECONTROL intrinsic is also supported on MPE/iX
systems with PAD connections. However, there are also several
limitations on the device control operations they perform. The following