Good, you can close down the Terminal program now. Go here if there are problems at this stage. Too many telephones the telephone line is capable of driving only so many devices at once, and the modem may be the one too many. It may be a question of the dial tone being too faint for the modem to hear. Remember, we may be able to hear it, but it may not.
Extension lead too long their resistance is often very high.
This may also be the case for extension wiring done on an amateur basis to provide another telephone socket. Try again in the master socket. Try here . Obviously, houses which are a long way from the exchange will suffer more resistance in the wire than those which are close to the exchange, so in Britain BT normally subjects the line to AGC, which automatically compensates for this. This is good for voice calls, but poor for modem calls.