Patent ID: 6868145

Claim:
An alphanumeric keyboard comprising: control circuity connectable to a telephone line; and a plurality of keys electrically coupled with said control circuity, each key being uniquely associated with an alphanumeric character from a set of alphanumeric characters including at least a plurality of letter characters, each alphanumeric character being representable as data by an alphanumeric code signal from a set of alphanumeric code signals, each alphanumeric character also being representable as a component of a telephone number by a telephone number dialing signal from a set of telephone number dialing signals in accordance with a mapping, the control circuitry being operative in response to the pressing of a key for a given alphanumeric character (1) in a first operating mode, to generate the alphanumeric code signal to which the given alphanumeric character is mapped, and (2) in a second operating mode, to generate the telephone number dialing signal to which the given alphanumeric character is mapped; said control circuitry being operative detect the presence or absence of an off hook condition and a call connection involving a telephone device coupled to said telephone line and to automatically enter the second operating mode when said telephone device connected to said telephone line is in an off-hook condition and no connection on the telephone line has been established, and the control circuitry is operative to automatically enter the first operating mode when the local telephone device is in an off-hook condition and a connection on the telephone line has been established.