초록 ▼

A telephone security system particularly for use with cordless telephone, operates to prevent the base station of the system from being accessed by an unauthorized user. Preselected digits are set by means of switches. In order to receive a dial tone, the correct digits as selected by the switches m

A telephone security system particularly for use with cordless telephone, operates to prevent the base station of the system from being accessed by an unauthorized user. Preselected digits are set by means of switches. In order to receive a dial tone, the correct digits as selected by the switches must be dialed. The security system operates to compare the dialed digits with those digits set by the switches. If a favorable comparison is had, the security device then connects the telephone line to the base station and allows dial tone to be transmitted to thereby enable a call to be implemented by the user.

대표청구항 ▼

In a cordless telephone system of the type having a base unit coupled to a telephone line and for transmitting to and receiving signals from a remote unit associated with said base unit, said remote unit also capable of transmitting to and receiving signals from said base unit, said base unit capabl

In a cordless telephone system of the type having a base unit coupled to a telephone line and for transmitting to and receiving signals from a remote unit associated with said base unit, said remote unit also capable of transmitting to and receiving signals from said base unit, said base unit capable of causing said telephone line to go “off-hook”when requested by said remote unit to cause dial tone to be transmitted to said remote unit, the combination therewith of apparatus for preventing the transmission of dial tone from said base unit to said remote unit until authorized, said apparatus comprising: means for storing a predetermined signal code in said base unit; means located in said base unit for receiving signals transmitted by said remote unit when it is desired to transmit a dial tone to said remote unit from said base unit, said signals including signals indicative of said predetermined code, and said means for receiving said signals including a first timing circuit operative to provide a timing interval of a given duration when a transition pulse is detected indicative of a dial signal, whereby if additional pulses are not received during said interval said telephone is inhibited from receiving said dial tone; means associated with said base unit for comparing said signals received from said remote unit with said stored signals indicative of said predetermined signal code in order to detect a favorable comparison therebetween; and means for activating said telephone line to transmit said dial tone from said base unit to said remote unit when a favorable comparison is made.