System for cable communication wherein interpretively coded data transmitted from headend selectively initiate loop free instruction sets stored in receiver-decoder to affect the behavior thereof

摘要

A television cable system includes a headend and a decoder coupled by an in-band communication link and an out of band communication link. The headend controller includes conventional transmission systems for providing a plurality of program channels to the decoder via the in- band communication link. In addition, the headend system includes a plurality of controller inputs which provide data to a download executive circuit which in turn organizes data and transfer it to a transmitter coupled to the out of band data link. Within the decoder, a pair of processors are operative via a communication link therebetween. One processor is of predefine capability and is used to operate a user keyboard as well as conventional tuning and signal processing and descrambling systems to provide television display. The remaining processor includes a memory manager coupled to an out of band transmission receiver which receives downloaded interpretive execution data. The decoder further includes a program memory and interpreter circuit operatively coupled to the memory manager. Downloaded data is presented to the interpreter by the dialogue processor which receives instructions in response from the interpreter to execute a particular instruction set or sequence group within the downloaded program. All instruction sets or sequence groups within the downloaded program are free of loops or branch backward instructions to avoid lockout problems.