help with 4.2 dmf autoanswer problem

[BostonU SysMgr]

>From: miorelli at pwa-b.UUCP (Bob Miorelli)
>Subject: help with 4.2 dmf autoanswer problem
>
>I have a problem with dialing into a system here.  The system is 4.2
>with a df03 auto-answer modem plugged into a dmf (3rd dmf, port 0, or
>ttyi0).  The modem answers fine and carrier locks on, but the
>carrier detect is never passed on to init.....

The first (obvious) thing to check is the wiring, the rs232 connector
might be defeating the signals (such connectors are common as sometimes
we want to do that.)

The second thing to check is your config, the flags field for the
device dmf entry indicates which ports are to be treated as modem
controlled and which as 'defeated' (eg. by wiring as above.) Note
also (your note seems to indicate that you understand this) only
ports 0 and 1 will work as you want in any case.

If a bit is *on* in the flags field it means 'defeated', off means modem
control, if you want to enable those two ports the right thing is:

	... flags 0xfc

tho extending to 16 bits probably won't hurt (0xfffc). You then have
to re-build your kernel (yeah, we all know, a kludge, should be settable
at any time.)

Beyond that it could be any number of things, I would check out the modem
next (borrow a different modem that you know works maybe.) Parity, etc etc.

	-Barry Shein, Boston University