Cable television system with two-way telephone communication path

[54] CABLE TELEVISION SYSTEM WITH TWO-WAY TELEPHONE COMMUNICATION PATH

[75] Inventor: Marc W. Kauffinan, Cheltenham, Pa.

[73] Assignee: General Instrument Corporation, New York, N.Y.

[21] Appl. No.: 801,574

[22] Filed: Not. 25, 1985

[51] Int. CI.4 H04N 7/167; H04N 7/10;

H04M 11/00

[52] U.S. CI 380/10; 235/382;

235/382.5; 358/84; 379/91; 379/92; 379/209;

380/20; 455/2

[58] Field of Search 358/122, 84, 86, 114;

179/2 AS, 2 AM; 455/2, 4; 235/382, 382.5;

380/10, 20; 379/91, 92, 209

[56] References Cited

U.S. PATENT DOCUMENTS

3,390,234 6/1968 Glidden 179/2 AM

3,684,823 8/1972 McVoy 358/84

3,769,579 10/1973 Harney 358/84

3,890,461 6/1975 Vogelman et al 358/115

4,104,486 8/1978 Martin et al 179/2 AM

4,126,762 11/1978 Martin et al 179/2 A

4,163,254 7/1979 Block et al 358/122

4,225,884 9/1980 Block et al 358/84

4,439,670 3/1984 Basset et al 235/382.5

4,484,217 11/1984 Block et al 358/84

4,486,625 12/1984 Reinauer et al 179/2 AM

4,546,382 10/1985 McKenna et al 358/86

Primary Examiner—Stephen C. Buczinski

Attorney, Agent, or Firm—Barry R. Lipsitz

[57] ABSTRACT

A method and apparatus to enable billing of subscribers of pay-per-view television systems or the like on a nonreal-time basis. A scrambled television signal is received at a subscriber terminal from a headend. The received signal is selectively descrambled in response to subscriber action indicating acceptance for viewing of a program contained in the signal. A record is maintained at the subscriber terminal of the billable programs accepted for viewing by the subscriber. The signal received from the headend is monitored by the subscriber terminal for a call-in command which instructs the subscriber terminal to forward the record of billable programs to the headend. A telephone communication path is established between the subscriber terminal and the headend in response to the call-in command. The record of billable programs is transmitted to the headend over the telephone communication path, and the subscriber is billed in accordance therewith. A plurality of transaction credits can be downloaded from the headend to the subscriber terminal, stored therein, and debited in response to the acceptance by a subscriber of a billable program for viewing. The descrambling of a program is prevented if there are not sufficient stored transaction credits available to pay for the program. A time-out count can be maintained in the subscriber terminal and reinitialized in response to a signal received from the headend. Descrambling of billable programs is prevented at the subscriber terminal if the time-out count expires.

32 Claims, 7 Drawing Figures