1. In a telephone system, a method for a first telephone extension monitoring operation of a second telephone extension that is communicating with another party, comprising the steps of while the second telephone extension is off hook and communicating with the another party, receiving by the first telephone extension a code identifying the second telephone extension; and in response to receipt of the code, copying information received by the second telephone extension to the first telephone extension so that the information is observable by a user of the first telephone extension.