phone is off hook when the apparatus is in an automatic block code dialing mode the user may override this setting and have his her caller id sent on a per call basis another aspect of the invention is a circuit arrangement which is capable of reducing the speech voice interference to the call waiting caller id alert signal during normal telephone conversation thus improving the chance of a successful caller id data transmission during call waiting application_number US 54053295 A description the general organization of one embodiment of the invention is illustrated in the block diagram of fig1 the apparatus includes a receiving transmitting and dialing circuitry 101 lcd display 102 mpu 103 block key 104 program key 105 code keys 106 delete key 107 tone buzzer 108 and phone line status detector 109 block key 104 is preprogrammed to generate a block code description on the lcd display and to dial the block code when the phone line is in an on hook status it is detected by the phone line status detector 109 pressing block key 104 causes the apparatus to display a blocking prompt e g 34 block 34 and the block code e g 34 67 34 that is lcd screen 102 displays 34 block 67 34 in this embodiment if the phone line is in an off hook status pressing block key 104 causes the device to dial the block code a confirmation message e g 34 block dialed 34 is also shown on lcd display 102 for the user 39 s benefit the device is programmable to operate in a 34 block code dialing prompt 34 mode in the preferred embodiment this mode is entered by pressing block key 104 and an extra code key 106 e g.