If you set the Receive Mode to Fax/Tel, you need to decide how long the machine will signal you with its special pseudo/double-ring when you have a voice call. If it's a fax call, the machine receives the fax.

This pseudo/double-ring happens after the initial ringing from the phone company. Only the machine rings and no other phones on the same line will ring with the special pseudo/double-ring. However, you can still answer the call on any telephone.