I have a 2821 router with Version 12.4(21) can't get the dial up to work
here is the config
Async0/1/0 unassigned YES NVRAM down down
line 0/1/0
session-timeout 10
password
modem InOut
modem autoconfigure discovery
transport input ssh
stopbits 1
speed 115200
flowcontrol hardware
Phone line test good