Digital data communication adapter

A method of controlling the transmission and reception of a frame of data in serial format, from a first processing terminal to at least one second processing terminal, respectively, comprising the steps of:

• generating and transmitting at said first processing terminal, a sequence of groups of signals containing an address code identifying said at least one second processing terminal to which a data transmission is directed, prescribed control information, and data to be received by said at least one second processing terminal, respectively;
• within the group of signals containing the data to be received by said at least one second processing terminal, selectively generating
• (i) a first sequence of signals representative of whether there is to be a change in the length of the data words,
• (ii) a second sequence of signals representative of the number of data words prior to the occurrence of a word length change, and
• (iii) a third sequence of signals containing each of said data words;
• receiving, at said at least one second processing terminal, the sequence of groups of signals transmitted by said first processing terminal and, upon recognizing that the address code contained within said sequence of groups of signals identifies said at least one second processing terminal, causing said sequence of groups of signals to be disassembled in accordance with any change in data word size as represented by said first and second sequences of signals;
• generating and transmitting, at said first processing terminal, a first groups of signals representative of a prescribed function of said sequence of groups of signals;
• generating and transmitting, at said first processing terminal, a pair of groups of flag signals each of which uniquely identifies an end point of a frame of data;
• so that each frame of data transmitted from said first processing terminal to said at least one second processing terminal is comprised of an initial flag signal group, a sequence of address, control, and data signal groups, a prescribed function signal group, and a terminating flag signal group at said at least one second processing terminal;
• monitoring signals from a first processing terminal and, upon detecting an initial flag signal group, comparing the address signal group with at least one receiver address code identifying said at least one second processing terminal to determine whether or not the signals from a first processing terminal are being directed to said at least one secured processing terminal;
• also at said at least one second processing terminal, selectively separating a received frame of data into its respective signal groups and generating a second group of signals representative of a preselected function of the received sequence of groups of signals;
• and
• comparing the first group of signals representative of said prescribed function of said sequence of groups of signals transmitted from a first processor terminal with said second group of signals representative of said preselected function of the received sequence of groups of signals, whereby the correlation of the received frame with that transmitted can be determined.

A method of controlling the transmission and reception of a frame of data in serial format, from a first processing terminal to at least one second processing terminal, respectively, comprising the steps of:

• generating and transmitting at said first processing terminal, a sequence of groups of signals containing an address code identifying said at least one second processing terminal to which a data transmission is directed, prescribed control information, and data to be received by said at least one second processing terminal, respectively;
• and
• within the group of signals containing the data to be received by said at least one second processing terminal, selectively generating
• (i) a first sequence of signals representative of whether there is to be a change in the length of the data words,
• (ii) a second sequence of signals representative of the number of data words prior to the occurrence of a word length change, and
• (iii) a third sequence of signals containing each of said data words;
• and
• receiving, at said at least one second processing terminal, the sequence of groups of signals transmitted by said first processing terminal and, upon recognizing that the address code contained within said sequence of groups of signals identifies said at least one second processing terminal, causing said sequence of groups of signals to be dissassembled in accordance with any change in the data word size as represented by said first and second sequences of signals;
• generating and transmitting, at said first processing terminal, a first group of signals representative of a prescribed function of said sequence of groups of signals;
• generating and transmitting, at said first processing terminal, a pair of groups of flag signals each of which uniquely identifies an end point of a frame of data;
• so that each frame of data transmitted from said first processing terminal to said at least one second processing terminal is comprised of an initial flag signal group, a sequence of address, control and data signal groups, a prescribed function signal group, and a terminating flag signal group;
• at said first processing terminal,
• selectively modifying said sequence of groups of signals and said first group of signals so as to prevent the frame of data from containing groups of signals corresponding to said flag signals other than at those portions of a data frame where flag signals are intended to occur, and
• at said at least one second processing terminal,
• detecting the occurrence of any selective modification of the sequence of groups of signals and said first group of signals transmitted from a first processing terminal and removing said selective modification thereof so as to permit accurate disassembly of a frame of data received at said at least one second processing terminal.

A method of controlling the transmission and reception of a frame of data in serial format, from a first processing terminal to at least one second processing terminal, respectively, comprising the steps of:

• generating and transmitting at said first processing terminal, a sequence of groups of signals containing an address code identifying said at least one second processing terminal to which a data transmission is directed, prescribed control information, and data to be received by said at least one second processing terminal, respectively;
• and
• within the group of signals containing the data to be received by said at least one second processing terminal, selectively generating
• (i) a first sequence of signals representative of whether there is to be a change in the length of the data words,
• (ii) a second sequence of signals representative of the number of data words prior to the occurrence of a word length change, and
• (iii) a third sequence of signals containing each of said data words;
• and
• receiving, at said at least one second processing terminal, the sequence of groups of signals transmitted by said first processing terminal and, upon recognizing that the address code contained within said sequence of groups of signals identifies said at least one second processing terminal, causing said sequence of groups of signals to be disassembled in accordance with any change in data word size as represented by said first and second sequences of signals;
• generating and transmitting, at said first processing terminal, a first group of signals representative of a prescribed function of said sequence of groups of signals;
• generating and transmitting, at said first processing terminal, a pair of groups of flag signals each of which uniquely identifies an end point of a frame of data;
• so that each frame of data transmitted from said first processing terminal to said at least one second processing terminal is comprised of an initial flag signal group, a sequence of address, control, and data signal groups, a prescribed function signal group, and a terminating flag signal group;
• at said first processing terminal,
• generating an abort character made up of a prescribed group of signals representative of the aborting of a frame in response to the occurrence of prescribed conditions, and transmitting said abort character to said at least one second processing terminal, and
• at said at least one second processing terminal,
• detecting an abort character transmitted from a first processing terminal and thereby terminating frame reception.

A data communication system for controlling the transmission and reception of a frame of data in serial format, from a first processing terminal whereat data to be transmitted is read out from a selectively addressable memory, said frame being comprised of a sequence of signal containing address, control, and data information fields, to at least one second processing terminal whereat received data is written into a selectively addressable memory, comprising:

• at said first processing terminal,
• first means for generating a first sequence of groups of signals containing the address of said at least one second processing terminal to which the transmission of a frame of data is directed, and prescribed control information, respectively,
• second means for accessing the selectively addressable memory and generating a second sequence of groups of signals respectively representative of whether there is to be a change in the length of the data words, the number of data words prior to the occurrence of a word length change, and the words containing the data information, and
• third means, coupled to said first and second means, for sequentially transmitting said first and second sequences of groups of signals to said at least one second processing terminal, and
• at said at least one second processing terminal,
• fourth means for monitoring signals transmitted by a first processing terminal and generating an output upon recognizing that the first sequence of groups of signals contains an address corresponding to said at least one second processing terminal, and
• fifth means, coupled to said fourth means, for causing a frame of data read out of memory and transmitted by said first processing terminal to be disassembled and written into memory at said second processing terminal in accordance with any change in data word size as represented by said second sequence of signals;
• sixth means, coupled to said first and second means, for generating a group of signals representative of a prescribed function of said first and second sequences of groups of signals and supplying said prescribed function representative group of signals to said third means for transmission subsequent to the transmission of said second sequence of groups of signals;
• seventh means, coupled to said third means, for generating a pair of groups of flag signals, each of which uniquely identifies an end point of a frame of data, and supplying one of said groups of flag signals to said third means for transmission prior to the transmission of said first sequence of groups of signals and the other of said groups of flag signals to said third means for transmission subsequent to the transmission of said prescribed function representative group of signals, so that a complete frame of data transmitted by said first processing terminal to said at least one second processing terminal is comprised of a sequential arrangement of said one of said groups of flag signals, said first sequence, said second sequence, said prescribed function representative group, and the other of said groups of flag signals;
• and
• said fourth means including means for comparing the address containing signal group with at least one receiver address code identifying said at least one second processing terminal, upon detection of said one flag signal group, to determine whether or not a frame of data transmitted from a first processing terminal is being directed to said at least one second processing terminal.

A data communication system for controlling the transmission and reception of a frame of data in serial format, from a first processing terminal whereat data to be transmitted is read out from a selectively addressable memory, said frame being comprised of a sequence of signals containing address, control, and data information fields, to at least one second processing terminal whereat received data is written into a selectively addressable memory, comprising:

• at said first processing terminal,
• first means for generating a first sequence of groups of signals containing the address of said at least one second processing terminal to which the transmission of a frame of data is directed, and prescribed control information, respectively,
• second means for accessing the selectively addressable memory and generating a second sequence of groups of signals respectively representative of whether there is to be a change in the length of the data words, the number of data words prior to the occurrence of a word length change, and the words containing the data information, and
• third means, coupled to said first and second means, for sequentially transmitting said first and second sequences of groups of signals to said at least one second processing terminal, and
• at said at least one second processing terminal,
• fourth means for monitoring signals transmitted by a first processing terminal and generating an output upon recognizing that the first sequence of groups of signals contains an address corresponding to said at least one second processing terminal, and
• fifth means, coupled to said fourth means, for causing a frame of data read out of memory and transmitted by said first processing terminal to be disassembled and written into memory at said second processing terminal in accordance with any change in data word size as represented by said second sequence of signals;
• sixth means, coupled to said first and second means, for generating a group of signals representative of a prescribed function of said first and second sequences of groups of signals and supplying said prescribed function representative group of signals to said third means for transmission subsequent to the transmission of said second sequence of groups of signals;
• seventh means, coupled to said third means, for generating a pair of groups of flag signals, each of which uniquely identifies an end point of a frame of data, and supplying one of said groups of flag signals to said third means for transmission prior to the transmission of said first sequence of groups of signals and the other of said groups of flag signals to said third means for transmission subsequent to the transmission of said prescribed function representative group of signals, so that a complete frame of data transmitted by said first processing terminal to said at least one second processing terminal is comprised of a sequential arrangement of said one of said groups of flag signals, said first sequence, said second sequence, said prescribed function representative group, and the other of said groups of flag signals;
• and
• eighth means, coupled to said fourth means, for monitoring the length of the frame of data and generating an invalid frame indicating signal upon recognition of said other flag signal group prior to the length of the monitored frame of data reaching a preselected value.

A data communication system for controlling the transmission and reception of a frame of data in serial format, from a first processing terminal whereat data to be transmitted is read out from a selectively addressable memory, said frame being comprised of a sequence of signals containing address, control, and data information fields, to at least one second processing terminal whereat received data is written into a selectively addressable memory, comprising:

• at said first processing terminal,
• first means for generating a first sequence of groups of signals containing the address of said at least one second processing terminal to which the transmission of a frame of data is directed, and prescribed control information, respectively,
• second means for accessing the selectively addressable memory and generating a second sequence of groups of signals respectively representative of whether there is to be a change in the length of the data words, the number of data words prior to the occurrence of a word length change, and the words containing the data information, and
• third means, coupled to said first and second means, for sequentially transmitting said first and second sequences of groups of signals to said at least one second processing terminal, and
• at said at least one second processing terminal,
• fourth means for monitoring signals transmitted by a first processing terminal and generating an output upon recognizing that the fist sequence of groups of signals contains an address corresponding to said at least one second processing terminal, and
• fifth means, coupled to said fourth means, for causing a frame of data read out of memory and transmitted by said first processing terminal to be disassembled and written into memory at said second processing terminal in accordance with any change in data word size as represented by said second sequence of signals;
• sixth means, coupled to said first and second means, for generating a group of signals representative of a prescribed function of said first and second sequences of groups of signals and supplying said prescribed function representative group of signals to said third means for transmission subsequent to the transmission of said second sequence of groups of signals;
• seventh means, coupled to said third means, for generating a pair of groups of flag signals, each of which uniquely identifies an end point of a frame of data, and supplying one of said groups of flag signals to said third means for transmission prior to the transmission of said first sequence of groups of signals and the other of said groups of flag signals to said third means for transmission subsequent to the transmission of said prescribed function representative group of signals, so that a complete frame of data transmitted by said first processing terminal to said at least one second processing terminal is comprised of a sequential arrangement of said one of said groups of flag signals, said first sequence, said second sequence, said prescribed function representative group, and the other of said groups of flag signals;
• eighth means, coupled to said third means, for selectively modifying said first and second sequences of groups of signals and said prescribed function representative group of signals so as to prevent a transmitted frame of data from containing groups of signals corresponding to said flag signals other than at those portions of a data frame where flag signals are intended to occur, and
• at said at least one second processing terminal,
• ninth means, coupled to said fourth means, for detecting the occurrence of any selective modification of said first and second sequences of groups of signals and said prescribed function representative groups of signals transmitted from a first processing terminal and removing said selective modification thereof so as to permit accurate disassembly of a frame of data by said fifth means.

A data communication system for controlling the transmission and reception of a frame of data in serial format, from a first processing terminal whereat data to be transmitted is read out from a selectively addressable memory, said frame being comprised of a sequence of signals containing address, control, and data information fields, to at least one secoond processing terminal whereat received data is written into a selectively addressable memory, comprising:

• at said first processing terminal,
• first means for generating a first sequence of groups of signals containing the address of said at least one second processing terminal to which the transmission of a frame of data is directed, and prescribed control information, respectively,
• second means for accessing the selectively addressable memory and generating a second sequence of groups of signals respectively representative of whether there is to be a change in the length of the data words, the number of data words prior to the occurrence of a word length change, and the words containing the data information, and
• third means, coupled to said first and second means, for sequentially transmitting said first and second sequences of groups of signals to said at least one second processing terminal, and
• at said at least one second processing terminal,
• fourth means for monitoring signals transmitted by a first processing terminal and generating an output upon recognizing that the first sequence of groups of signals contains an address corresponding to said at least one second processing terminal, and
• fifth means, coupled to said fourth means, for causing a frame of data read out of memory and transmitted by said first processing terminal to be disassembled and written into memory at said second processing terminal in accordance with any change in data word size as represented by said second sequence of signals;
• sixth means, coupled to said first and second means, for generating a group of signals representative of a prescribed function of said first and second sequences of groups of signals and supplying said prescribed function representative group of signals to said third means for transmission subsequent to the transmission of said second sequence of groups of signals;
• seventh means, coupled to said third means, for generating a pair of groups of flag signals, each of which uniquely identifies an end point of a frame of data, and supplying one of said groups of flag signals to said third means for transmission prior to the transmission of said first sequence of groups of signals and the other of said groups of flag signals to said third means for transmission subsequent to the transmission of said prescribed function representative group of signals, so that a complete frame of data transmitted by said first processing terminal to said at least one second processing terminal is comprised of a sequential arrangement of said one of said groups of flag signals, said first sequence, said second sequence, said prescribed function representative group, and the other of said groups of flag signals;
• eighth means, coupled to said third means, for generating an abort character made up of a prescribed group of signals representative of the aborting of a frame, in response to the occurrence of prescribed conditions, and supplying said abort character to said third means for immediate transmission to said at least one second processing terminal, and
• at said at least one second processing terminal,
• ninth means, coupled to said fourth and fifth means, for detecting an abort character transmitted from a first processing terminal and terminating frame reception and disassembly in response thereto.

A method of controlling the transmission of a frame of data in serial format from a first processing terminal to at least one second processing terminal comprising the steps of:

• generating and transmitting at said first processing terminal, a sequence of groups of signals containing an address code identifying said at least one second processing terminal to which a data transmission is directed, prescribed control information, and data to be received by said at least one second processing terminal, respectively;
• and
• within the group of signals containing the data to be received by said at least one second processing terminal, selectively generating
• (i) a first sequence of signals representative of whether there is to be a change in the length of the data words,
• (ii) a second sequence of signals representative of the number of data words prior to the occurrence of a word length change, and
• (iii) a third sequence of signals containing each of said data words;
• generating and transmitting, at said first processing terminal, a first group of signals representative of a prescribed function of said sequence of groups of signals;
• generating and transmitting, at said first processing terminal, a pair of groups of flag signals each of which uniquely identifies an end point of a frame of data;
• so that each frame of data transmitted from said first processing terminal to said at least one second processing terminal is comprised of an initial flag signal group, a sequence of address, control, and data signal groups, a prescribed function signal group, and a terminating flag signal group;
• at said first processing terminal;
• selectively modifying said sequence of groups of signals and said first group of signals so as to prevent the frame of data from containing groups of signals corresponding to said flag signals other than at those portions of a data frame where flag signals are intended to occur,
• generating an abort character made up of a prescribed group of signals representative of the aborting of a frame, in response to the occurrence of prescribed conditions, and transmitting said abort character to said at least one second processing terminal.

A data communication system for controlling the transmission of a frame of data in serial format from a first processing terminal to at least one second processing terminal, said frame being comprised of a sequence of signals containing address, control, and data information fields, comprising:

• at said first processing terminal,
• first means for generating a first sequence of groups of signals containing the address of said at least one second processing terminal to which the transmission of a frame of data is directed, and prescribed control information, respectively,
• second means for accessing the selectively addressable memory and generating a second sequence of groups of signals respectively representative of whether there is to be a change in the length of the data words, the number of data words prior to the occurrence of a word length change, and the words containing the data information;
• third means, coupled to said first and second means, for sequentially transmitting said first and second sequence of groups of signals to said at least one second processing terminal;
• fourth means, coupled to said first and second means, for generating a group of signals representative of a prescribed function of said first and second sequences of groups of signals and supplying said prescribed function representative group of signals to said third means for transmission subsequent to the transmission of said second sequence of groups of signals;
• fifth means, coupled to said third means, for generating a pair of groups of flag signals, each of which uniquely identifies an end point of a frame of data, and supplying one of said groups of flag signals to said third means for transmission prior to the transmission of said first sequence of groups of signals and the other of said groups of flag signals to said third means for transmission;
• sixth means, coupled to said third means, for selectively modifying said first and second sequences of groups of signals and said prescribed function representative group of signals so as to prevent a transmitted frame of data from containing groups of signals corresponding to said flag signals other than at those portions of a data frame where flag signals are intended to occur;
• and
• seventh means, coupled to said third means, for generating an abort character made up of a prescribed group of signals representative of the aborting of a frame, in response to the occurrence of prescribed conditions, and supplying said abort character to said third means for immediate transmission to said at least one second processing terminal.