Though the default modem initialisation string worked fine for my hardware 56K modem on /dev/ttyS0, it didn't work at all with my pcmcia modem on /dev/ttyS1
I described my difficulties (and details of the changes I needed to make) in my post here:
http://forum.tinycorelinux.net/index.php?topic=311.msg5816#msg5816In brief, I used the modem initialisation string which I discovered is used by default in Puppy Linux version 2.17.1, which I repeat here for your convenience (in the form expected by the pppsetup script):
ATZ OK "ATQ0 V1 E1 S0=0 &C1 &D2 S11=55 +FCLASS=0" OK
Please visit the above link to my earlier post for more details along with a solution to another unexpected problem I had with my ISPs ppp negotiation requirements.
NOTE: Since the above modem initialisation string seems to work with a large variety of modems, I hope you will modify pppsetup to use that by default rather than the modem string currently suggested (which didn't play nicely with my pcmcia modem on /dev/ttyS1 at all).
Please also remember to include bash as one of the dependencies for pppsetup to run successfully.