in-out modems on SPARC

[Eugene D. Brooks III]

We finally resolved the problem.  The key is using ttysoftcar to put the
carrier handling of the tty lines connected to modems in the right mode.
Assuming you have created the ttyd# and cua# device files according to the
manual and that you have set the eeprom parameters as directed in the
manual, you remove the "local" field from the entries in the ttytab file
for the ttyd# lines.  You then execute "ttysoftcar -a" once and it appears
to put the tty lines in the right state with respect to carrier handling.
When done you get dialin lines which respect the carrier and deliver
hangup properly, while being able to dialout on the companion cua# lines
if the corresponding ttyd# line does not have a login active on it.

NOTE:  Once ttysoftcar is used to cause the line to respect the carrier
properly, any attempt to use ttysoftcar on the affected line will hang as
an open will now block waiting for carrier.  If you want to turn the
status of the line back around you have to dial in on the modem and run
ttysoftcar while the carrier is up on the line.  Its real neat how things
work, ain't it!