If you are trying to get the 803 to
request callback from the router, all
that you need configure is "ppp callback
request". Note that the 803 does not
support MS Callback Client mode (this
is CSCdm05122).
If you are trying to get the 803 to
callback a device, check out "debug
ppp neg", "deb callback", and "debug
ppp cbcp" to see what is happening.
The commands required for callback are
"ppp callback accept" and callback
authorization which is accomplished
with either a username with a
callback-string, or via AAA.