cty(4)cty(4)Namecty - extra serial line interface
The extra serial lines are available to the processor through the con‐
sole registers. These lines are available on the VAX 8100, 8200, 8300,
8500, 8550, 8600, 8650, 8700, and 8800 machines and number three all
total. They act like normal terminal lines, except for the VAX 8600
(8650), where the first line can also act as a remote console port and
the other two lines are currently unused. Entries for these lines
should be placed in if they are used.
There are also certain workstation configurations that may use the con‐
sole serial interface. For MicroVAX workstation configurations, call‐
ing with the argument ttycp will create the device special file needed
to utilize the console interface. Before using the serial line inter‐
face, it is important to consider the setting of the halt enable switch
on a MicroVAX workstation.
In general, the lines are low-performance devices. They can be used as
terminal ports, but, for each character sent or received, the CPU is
interrupted. Thus, it is recommended that the extra serial lines be
used at low baud rates (2400 baud or less), so that console input and
output do not severely impact system performance.
FilesSee Alsoconsole(4), tty(4), MAKEDEV(8)