US 5,499,287 A · FAX-telephone interface circuit

Abstract

An improved telephone interface box which interfaces an incoming telephone line to either a modem or a telephone handset is disclosed. The choice of connection is made by a controller that answers incoming calls and determines if the call is to be directed to the modem or the telephone line. The controller determines the destination of the incoming call by detecting tones on the telephone line or by examining the response of the caller to a voice prompt. If the controller determines that the incoming call is to be directed to the telephone handset, the controller generates a ring signal having substantially the same cadence as that detected on the incoming line and sends that ring signal to the telephone handset. If the handset goes off-hook during the time the controller is making its determination as to the correct destination for the incoming call, the controller suspends its operation until the handset is placed on-hook or a predetermined time interval elapses. The controller also allows the handset to assert priority over an existing connection by rapidly depressing the off-hook switch on the handset.

Claims3

Dependent claims

An apparatus for connecting a modem and a telephone handset to a telephone line, said apparatus comprising:

means for coupling said apparatus to said telephone line;
means for coupling said apparatus to said modem;
means for coupling said apparatus to said telephone handset;
switch means, responsive to a switch control signal, for connecting either said telephone handset or said modem to said telephone line;
means for detecting a ring signal on said telephone line;
off-hook detecting means for detecting if said telephone handset is off-hook, said off-hook condition being indicated by an off-hook signal generated by said off-hook detecting means;
and
control means, responsive to said ring signal detecting means, for determining if a telephone call received on said telephone line is to be directed to said handset or said modem and for generating said switch control signal, wherein said control means further comprises means for detecting a sequence of off-hook signal pulses and wherein said control means terminates any connection between said telephone line and said modem and causes said switch means to couple said telephone handset to said telephone line when said sequence of off-hook signal pulses is detected thereby allowing said telephone handset to be used to initiate a telephone call on said telephone line.

5 more elements

Dependencies are inferred from the claim text.

FAX-telephone interface circuit

Life of this patent

FAX-telephone interface circuit

Life of this patent

Abstract

Claims3