Likely Cause Connection refused. To force the line back into an idle state, clear the line from the console and try again. If it still fails, ensure that you have set modem inout command for that line. As a last resort, disconnect the modem, clear the line, make the Telnet connection, and then attach the modem. The prevents a misconfigured modem from denying you line access.
Connection appears to hang.
EXEC does not come up, autoselect is on. Modem does not hang up after entering quit . The modem is either not receiving DTR information, or you have not set up modem control on the router. Interrupt another user's session when you dial in. The modem is either not dropping CD on disconnect, or you have not set up modem control on the Cisco router.