Telephone conversion unit with multiple memory system

• US 4,008,380 A
• Filed: 06/30/1975
• Issued: 02/15/1977
• Est. Priority Date: 06/30/1975
• Status: Expired due to Term

• Current Assignee: ROOD Tool Company
• Original Assignee: ROOD Tool Company
• Inventors: La Borde, Richard C.
• Primary Examiner(s): Robinson, Thomas A.
• Application Number:
  US05/592,056
• Time in Patent Office: 596 Days
• Field of Search: 179/90 B, 179/90 BB, 179/90 BD, 179/90 K, 179/90 R, 179/2 DP
• US Class Current: 379/353
• CPC Class Codes: H04M 1/312 pulses produced by electronic circuits

Abstract

A telephone conversion unit for substitution in a standard rotary dial telephone is disclosed wherein a keyboard coded telephone number is converted to a serial pulse train which simulates that generated by a standard telephone rotary dialer unit. The converter includes a keyboard switch having at least 10 keys for generating signals corresponding to each key depressed. An electrical encoder converts the signals into a four bit parallel signal with each encoded signal uniquely identifying a depressed one of the 10 keys of the keyboard. A dialer circuit means converts the encoded signal to a serial pulse train corresponding to the respective keys depressed. Power for the conversion unit is provided by converting the telephone line current coupled to the telephone unit when the hook switch is closed to a voltage suitable for powering the converter unit. A memory means is provided wherein when a memory control key of the keyboard switching means is depressed, the number keyed is stored in a location of the memory selected by the subsequent depression of one of the keys of the keyboard. The number can be retrieved from memory and coupled to the dialer means by momentarily depressing the memory control key and the key which addresses location in memory in which the number to be dialed is located. Mechanically the conversion unit together with the memory means can be positioned in a standard dial telephone unit by substitution of the conversion means in place of the dialer.

Claims

1. In a conventional telephone unit, a converter positioned therein in place of a rotary dialer unit for converting a keyboard coded telephone number to a serial pulse train corresponding to the type generated by said rotary dialer unit, said converter comprising:

a. a keyboard switching means having at least ten keys for generating signals corresponding to each of said keys as said keys are depressed,

b. an electrical encoder means for converting said signals into parallel four bit signals, each encoder signal uniquely identifying a depressed one of said ten keys,

c. a dialer circuit means for converting said encoded signals to a serial pulse train corresponding to the respective keys depressed,

d. a bridge rectifier for rectifying the telephone line current conducted to said telephone unit,

e. means for generating a supply voltage for said converter, said voltage generating means including means for converting telephone line current coupled to said telephone unit to a voltage only when the hook switch of said telephone unit is closed, and voltage multiplying means for increasing said voltage to a preselected voltage level,

f. a first switch for inhibiting current flow through said telephone unit when said dialer generates said pulse train,

g. second switching means connected across said telephone unit for interrupting current flow in said telephone lines in accordance with said pulse train, and

h. a support structure adapted for positioning in a standard telephone unit in place of a rotary dialer, said support structure supporting said converter in said telephone unit housing.

2. The telephone converter of claim 1 wherein said encoder generates a strobe pulse each time a key is depressed, and further comprising a tone generator for generating a tone signal and gating means connected to the output of said tone generator at the input thereof and to the input of a speaker in said telephone at the output thereof, said strobe pulse enabling said gating means when a key is depressed to thereby conduct said tone signal to said speaker to confirm a switching action upon the depression of one of said keys.

3. The telephone converter of claim 2 further comprising a memory means for storing at least ten telephone numbers therein, and a memory control means responsive to the depressing of a storage control key for enabling said memory to store a keyed telephone number or to read out a stored telephone number into said dialer unit.

4. The converter of claim 3 further comprising battery means for storing a portion of the telephone line current coupled to said telephone unit when said hook switch of said telephone unit is closed, said means including a zener diode connected in series with said telephone lines and in parallel with said battery, said zener diode causing a portion of said line current to be stored in said battery when the charge level of said battery goes below a predetermined level, said battery providing a power supply voltage to said converter.

5. The converter of claim 4 wherein said memory control means generates a first storage command signal for enabling said memory to store a keyed telephone number when said storage control key is continuously depressed and for inhibiting the operation of said dialer circuit means, said memory control means retrieving a stored telephone number when said storage control key is momentarily depressed.

6. In a conventional telephone unit having a hand set receiver removably positioned with respect thereto, a hook switch closable when said hand set receiver is removed from the telephone unit, and current conducting telephone lines for conducting bipolar information with respect to said telephone unit, a converter positioned therein in place of a rotary dialer unit for converting a keyboard coded telephone number to a serial pulse train corresponding to the type generated by said rotary dialer unit, said converter comprising:

a keyboard switching means having at least ten keys for generating signals corresponding to each of said keys as said keys are depressed,

an electrical encoder means for converting said signals into parallel four bit signals, each encoder signal uniquely identifying a depressed one of said ten keys,

a dialer circuit means for converting said encoded signals to a serial pulse train corresponding to the respective keys depressed,

a bridge rectifier for rectifying the telephone line current conducted to said phone unit,

means for generating a supply voltage for said converter, said voltage generating means including means for converting telephone line current coupled to said telephone unit to a voltage only when the hook switch of said telephone unit is closed, and voltage adjusting means for increasing said voltage to a preselected voltage level,

a first switch for inhibiting current flow through said telephone unit when said dialer generates said pulse train,

second switching means connected across said telephone unit for interrupting current flow in said telephone lines in accordance with said pulse train, and

a support structure adapted for positioning in a standard telephone unit in place of a rotary dialer, said support structure supporting said converter in said telephone unit housing.