Telephone hold circuit
OwnerWilliam A. Curtisinventor
Life of this patent
Estimating the term…
Abstract
An electronic hold circuit for a telephone which is actuated by a hold command signal produced by a momentary depression of the telephone hook switch. The hold circuit is connected across the telephone lines and includes circuitry for discriminating between a hold command signal present on the telephone lines and dialing, ringing and hand-up signals. When a hold command signal is detected, a holding impedance is connected across the telephone lines thereby maintaining the connection at the central office.
Claims12
A hold circuit for use with a telephone, the telephone being connected to central office switching equipment via telephone lines and provided with a hook switch for switching the telephone between an on-hook and an off-hook condition, said hold circuit comprising:
- a hold command detecting means for detecting a hold command signal which is generated when a user activates the hook switch so as to momentarily place the telephone in an on-hook condition, said hold command detecting means including:
- (i) on/off hook detecting means for detecting when the telephone is in an on-hook and an off-hook condition;
- (ii) dialing signal filter means for discriminating between a hold command signal and a dialing signal;
- (iii) gating means responsive to said on/off hook detecting means and to said dialing signal filter means for producing a first output signal when either a hold command signal or a telephone hang-up signal is present on the telephone lines;
- (iv) discriminating means responsive to said first output signal for discriminating between a hold command signal and a telephone hang-up signal;
- and
- holding means coupled to the telephone lines, said holding means being a means for producing an on-hold condition when a hold command signal is detected by said discriminating means wherein the central office switching equipment is caused to maintain a connection with the telephone.
A hold circuit for use with a telephone, the telephone being connected to central office switching equipment via telephone lines and provided with a hook switch for switching the telephone between an on-hook and an off-hook condition, and wherein a hold command signal may be produced on the telephone line when the user momentarily places the telephone in an on-hook condition, said hold circuit comprising:
- on/off hook detecting means for producing a first signal indicative of whether the telephone is in an on-hook or an off-hook condition, said first signal being independant of any ringing signal on the telephone line;
- dialing signal filter means for producing a second signal when ringing signals or hold command signals are present on the telephone line, said second signal being independant of any dialing signal on the telephone line;
- discriminating means responsive to said first and second signals for discriminating between a hold command signal and a telephone hang-up signal and for producing a third signal when a hold command signal is present on the telephone lines;
- and
- holding means coupled to the telephone lines and responsive to said third signal, said holding means being a means for producing an on-hold condition when a hold command signal is on the telephone line wherein the central office switching equipment is caused to maintain a connection with the telephone.
Dependencies are inferred from the claim text.