Apparatus for inserting instructions in a control sequence in a stored program controlled telecommunication system

Claim 1

In a stored program controlled equipment having an operating device to be controlled, a clock pulse generator for generating sequences of timing pulses wherein adjacent timing pulses within one of the sequences establishes the clock pulse period of the equipment, an addressed memory means having an address input, an instruction output and a plurality of addressed memory element groups for storing control instructions which are read in responsive to received addresses, an address generator means having an input means and an output means and being response to said timing pulses for sequentially generating said addresses of the memory element groups to be read, and an instruction decoder means having an input and a plurality of outputs for generating control signals, apparatus for introducing one of a plurality of insertion instructions at a point in the sequence of control instructions, said apparatus comprising: a first memory element group in the memory means for storing the insertion instruction; means for storing the address of said first memory element group; and a logical buffer unit, said logical buffer unit comprising a logical switching means having first and second address inputs for receiving addresses, an output for transmitting the address received by one of the address inputs, and a control input for controlling which of the received addresses is transmitted, a buffer register means having an input for receiving information including at least the address of an instruction and an output for transmitting therefrom after a one-clock pulse period the information received at its input, means for connecting the output of said logical switching means to the input means of said address generator means, means for connecting the output means of said address generator means to the first address input of said logical switching means, means for connecting an output of the instruction decoder means to the control input of said logical switching means, means for connecting an output of the instruction decoder means to the second address input of said logical switching means, means for connecting the output means of said address generator means to the address input of the addressed memory means, means for connecting the instruction output of the addressed memory means to the input of said buffer register means, means for connecting the output of said buffer register means to the input of the instruction decoder means, controlled gating means having a control input for connecting said means for storing the address of said first memory element group to the second address input of said logical switching means, and means for connecting an output of the instruction decoder means to the control input of said controlled gating means; a second memory element group having an address at said point in the sequence of control instructions, said second memory element group storing first indicia for indicating that an insertion reference is to be performed and second indicia for indicating that the address of said first memory element group should be fetched; and a third memory element group having the next address after the point, said third memory element group storing said first indicia and third indicia for indicating the address of the next control instruction in the sequence; said decoder means decoding said first indicia to a signal fed to the control input of said logical switching means, decoding said second indicia to a signal fed to the control input of said controlled gating means, and feeding said third indicia to the second address input of said logical switching means whereby an insertion instruction is introduced into the sequence of control instructions.