Modem probs on Sun 3/60

[beeston at fst.icl.stc.co.uk]

Can anyone out there help me with this problem ?  I have a 2 Hayes
compatible modems (300/300,1200/75 Baud), which I have connected to the
serial ports of a Sun 3/60. One is for dial-out (ttya), and the other for
dial-in (ttyb).  After following through the procedures in the Sun
system-admin manual to setup the modems, the dial-out line worked fine,
but I seem to have major problems with the dial-in side of things.  When
the kernel I try to dial the modem up, it answers, but drops the line
almost instantly before a getty/login message appears, whether the kernel
is set for hardware or software carrier detect on ttyb.  I've tried
messing about with a breakout box on this line, and have found that by
switching off the Tx and Rx lines, the modem doesn't drop the line, but
then you can't type anything in, or receive anything.

Sun sent me a patch tape to 'fix' this problem, but it doesn't work.

Any ideas ???

PS. The eventual goal of this exercise is to have a dial-back script
running on the out-going modem. Does anyone have one of these working ???

[[A dialback routine was submitted some time back to the Sunspots archives
and may be retrieved from titan.rice.edu (/sun-source/dialback.shar). [see
Sunspots v8n127]. There is also a dialback routine available as part of
the SUG tape [see Sunspots v9n3]. -bdg]]