poff & rmmod ltmodem, script problem

[Marvin Stodolsky <stodolsk@erols.com>]

When I ppp connect through a Lucent Tech Winmodem, the
sequence is:

   insmod -f ltmodem
with force (-f) necessary because the supplied binary
ltmodem.o is not matched with  my kernel-2.2.14
    pon
can then complete the connection with the modules autoloaded
being:
sound                  56088   0  (autoclean) (unused)
soundlow                 300   0  (autoclean) [sound]
soundcore               2340   3  (autoclean) [sound]
ppp_deflate            39108   1  (autoclean)
ppp                    19916   2  (autoclean) [ppp_deflate]
slhc                    4200   1  (autoclean) [ppp]
ltmodem               452936   1   <<< manually loaded

When the connection is terminated with poff,
the cron/automated module removal "rmmod -a"  doesn't work,
at least until I manually  "rmmod ltmodem"
I tried a script:

#! /bin/sh
# to remove the the forced ltmodem.o as quickly as possible
poff && rmmod ltmodem
rmmod -a

but evident implementing some pause after the poff command
is necessary, before the ltmodem will unload.  Thereafter
rmmod -a  does unload the rest.
What's the appropriate way of doing implementing the desired
pause in script?

Please respond to stodolsk@erols.com as well as the list.

MarvS