pppd won't reset (or hang up) the modem

[Alexander Lobkovsky <lobkovsk@itp.ucsb.edu>]

Hi,

I don' think this came up before.  My ISP changed to a pap style
authorization and the only thigs I had to change was to add a 'user
guest' line to the /etc/ppp.options_out file and a line '*  *
password' to the /etc/ppp/pap-secrets file.  Now the modem does not
hang up if SIGINT is sent to pppd (it worked before).

Is this a problem on my side or the ISP side?

I tried to manually reset the modem (or hang up) so that I can stick
this command into a disconnect script, to no avail, what am
I doing incorrectly? I tried:

lobkovsk@fuzichka[3]~% echo ATZ > /dev/ttyS1

or

lobkovsk@fuzichka[3]~% echo ATH > /dev/ttyS1

or 

lobkovsk@fuzichka[3]~% echo -e '+++\nATH' > /dev/ttyS1

or

lobkovsk@fuzichka[3]~% chat '' 'ATZ'

none of these reset the modem.

If I enter minicom, for example, it has no problem reseting the modem.

thanks for your help,
-alex