LAN with interoperative multiple operational capabilities

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the interface means at the nodes between which communication occurs selects one of the first or second protocol for information communication;
• communicating information between nodes occurs by transmitting and receiving frames;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhances node;
• each node which is not an enhanced node is a basic node;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• each frame communicated in the first protocol having signals occurring in the intervals appropriate to the first protocol, each frame communicated in the second protocol having signals occurring in the intervals appropriate to the second protocol, the signals in the intervals defining symbols, the symbols including:
• a silence symbol which is common to both the first and second protocols and which indicates the absence of a physical signal, a basic symbol indicating the presence of a physical signal of some magnitude greater than the absence of a physical signal and which is common to both the first and second protocols, a common symbol indicating either a silence or a basic symbol, a unique symbol indicating at least one predetermined physical signal of magnitude different than the common symbol and which is present only in the second protocol, and a set symbol indicating the presence of a common or a unique symbol but not a silence symbol;
• all basic frames communicated in the first protocol are repetitions of one of common or silence symbols at consecutive intervals;
• and
• all enhanced frames communicated in the second protocol include an inserted symbol which is other than a silence symbol and which is inserted in at least one interval corresponding to the location of one of the silent symbols of a basic frame.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group plurality of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• the first protocol for communication of a data packet frame between a source node and a destination node requires an inquiry frame sent from the source node to the destination node, followed by a response frame sent from the destination node to the source node, followed by a data packet frame sent from the source node to the destination node, followed by a response frame acknowledging successful receipt of the data packet sent from the destination node to the source node;
• and
• the second protocol for communication of a data packet frame from an enhanced source node to an enhanced destination node requires a data packet frame sent from the enhanced source node to the enhanced destination node, followed by one of either an affirmative or negative response frame from the destination node to the source node indicating the successful or unsuccessful receipt of the data packet, respectively.

A local area network or LAN of the token passing variety, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group plurality of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group plurality of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes, each node of the second group is an enhanced node;
• communicating information between nodes occurs by transmitting and receiving frames;
• a token frame designated as a token is communicated among the interface means of the basic and enhanced nodes in a normal token loop to control access to the communication medium for communication between selected nodes;
• the token frame includes information of the status of each enhanced node which passes the token;
• and
• the second protocol allows the interface means associated with each enhanced node to redirect the token out of the normal token loop in accordance with the status information in the token.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group plurality of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• communicating information between nodes occurs by transmitting and receiving frames, each frame including at least one field;
• data is communicated between nodes in a data packet frame;
• a data packet frame communicated in the second protocol includes an error correcting code in a field of the data packet frame;
• and
• a data packet frame communicated in the first protocol does not include an error correcting code.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• and
• broadcast frames are communicated only in the first protocol between all of the nodes.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• the second protocol requires each enhanced node to communicate with other enhanced nodes using a frame containing status information regarding the capability of that enhanced node to transmit and receive frames;
• and
• the first protocol does not require any node to communicate status information regarding the capability of that node to transmit and receive frames.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• the second protocol requires each enhanced node to communicate with other enhanced nodes using a frame containing rate information at which the enhanced node can receive data;
• and
• the first protocol does not require any node to communicate rate information at which any node can receive data.

A local area network of LAN of the token passing variety, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• a token frame designated as a token is communicated among the interface means of the basic and enhanced nodes in a loop to control access to the communication medium for communication between selected nodes;
• the second protocol allows the token to be passed from one enhanced node to another enhanced node at the highest rate capability which the enhanced node can receive the token;
• and
• the first protocol requires that the token be passed from each basic node at one predetermined rate.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• the second protocol requires the interface means of each enhanced source node to insert a calibration signal periodically in each enhanced frame;
• the second protocol requires the interface means of each enhanced destination node to utilize the calibration signal to adjust a receiver at the enhanced destination node;
• and
• the first protocol does not require any calibration signal to adjust a receiver at a basic destination node.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• all enhanced frames communicated in the second protocol include a unique symbol which is present only in the second protocol;
• and
• the interface means of each enhanced node includes:
• means for determining whether all frames received at the enhanced node include the unique symbol,
• means for decoding the frame as an enhanced frame upon determining that the unique symbol is present in the frame;
• and
• means for decoding the frame as a basic frame upon determining that the unique symbol is not present in the frame.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• the interface means of each enhanced node includes:
• memory means containing capability information of at least some of the other enhanced nodes,
• means for determining from the memory means if the destination node to which a frame is to be transmitted from the enhanced node is an enhanced node and what capability information is associated with the enhanced destination node, and
• means for selecting the rate of the transmission of the frame by the enhanced node to the destination node based on the capability information determined from the memory means.

A local area network or LAN of the token passing variety, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• PG,137
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each node which is not an enhanced node is a basic node;
• each enhanced node has the capability to communicate in compliance with both the first and second protocols;
• communicating information between nodes occurs by transmitting and receiving frames;
• a token frame designated as a token is communicated among the interface means in a loop to control access to the communication medium for communication of frames between selected nodes;
• the token selectively communicates capability information regarding an enhanced node;
• the interface means of the enhanced nodes detect and decode the capability information;
• and
• the interface means of the basic nodes do not detect the capability information, and the capability information dues not interfere with the function of the token in achieving medium access control.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each enhanced node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• and
• the signals in enhanced frames which create the appearance of network operational activity in both protocols cannot be interpreted by the interface means at basic nodes as valid information.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the interface means of all nodes communicate information in frames in both protocols;
• and
• at least some of frames available for communication in one protocol are different than the frames available for communication in the other protocol.

A local area network or LAN, comprising:

• a plurality of nodes;
• a communication medium connecting the nodes;
• interface means associated with each of the nodes and operative for supplying signals defining frames to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a selected one of either a first or a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in both protocols in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• communicating information between nodes occurs by transmitting and receiving frames;
• all of said nodes have the capability of communicating information in frames in both protocols;
• and
• the number of frames available for communication in one protocol are different than the number of frames available for communication in the other protocol.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• communicating information between nodes occurs by transmitting and receiving frames;
• one frame communicated in the second protocol achieving a communication function corresponding to that communication function achieved by a frame communicated in the second protocol;
• each frame includes a plurality of fields, the frames which achieve corresponding communication functions in both protocols each have at least one similar field;
• and
• the similar field of a frame communicated in the second protocol has the capability of communicating more information than the similar field of the corresponding frame communicating in the first protocol.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• communicating information between nodes occurs by transmitting and receiving frames, some of the frames are transmitted sequentially in both protocols;
• sequentially transmitted frames are spaced by an interframe gap of a predetermined time interval;
• and
• the time length of the interframe gap between sequentially transmitted frames communicated in the first protocol is different than the time length of the interframe gap between sequentially transmitted frames communicated in the second protocol.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a second predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each enhanced node which is not an enhanced node is a basic node;
• communicating information between nodes occurs by transmitting and receiving frames;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• all basic frames communicated in the first protocol are formed of signals defining basic symbols;
• all enhanced frames communicated in the second protocol are formed of signals defining enhanced symbols, the enhanced symbols include a unique symbol which is present only at a predetermined location in enhanced frames communicated the second protocol;
• and
• the interface means of enhanced node includes:
• means responsive to a symbol at the predetermined location where the unique symbol is present in enhanced frames and operative for detecting the capability of a path through the communication medium for communicating enhanced frames upon decoding the symbol at the predetermined location as a unique symbol, and operative for detecting the lack of capability of a path through the communication medium for communicating enhanced frames upon decoding the symbol at the predetermined location as a basic symbol which is present in the first protocol.

A local area network or LAN, comprising:

• a plurality of at least three nodes which include a first group having at least two of said nodes therein and a second group having at least two of said nodes therein;
• a communication medium connecting the nodes;
• interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity and for communicating information between selected nodes in predetermined signals applied at selected regularly occurring intervals in compliance with a first predetermined communication protocol;
• and wherein:
• the first and second protocols are different;
• and
• the signals are applied in predetermined patterns to create network operational activity in both protocols while simultaneously communicating information in a selected one of the first or second protocols;
• the interface means at the nodes between which communication occurs selects one of the first or second protocol for information communication;
• communicating information between nodes occurs by transmitting and receiving frames;
• the first group of nodes includes all of the nodes;
• the second group of nodes includes less than all of the nodes;
• each node of the second group is an enhanced node;
• each enhanced node which is not an enhanced node is a basic node;
• the interface means of the basic nodes communicate information to basic nodes in basic frames in the first protocol;
• the interface means of the enhanced nodes communicate information to the basic nodes in basic frames in the first protocol and selectively communicate information to enhanced nodes in enhanced frames in the second protocol;
• each frame communicated in the first protocol having signals occurring in the intervals appropriate to the first protocol, each frame communicated in the second protocol having signals occurring in the intervals appropriate to the second protocol, the signals in the interval defining symbols, the symbols including one which is common to both the first and second protocols and which indicates the absence of a physical signal designated as a silence symbol, one indicating the presence of a physical signal of some magnitude greater than the absence of a physical signal and which is common to both the first and second protocols designated as a basic symbol, one indicating either a silence or a basic symbol designated as a common symbol, one indicating at least one predetermined physical signal of magnitude different than the common symbol and which is present only in the second protocol designated as a unique symbol, and one indicating the presence of a common or a unique symbol but not a silence symbol designated as a set symbol;
• the signals are applied in the first protocol in every other interval;
• the signals are applied in the second protocol in every consecutive interval;
• the intervals are of the same time duration in the first and second protocols;
• all basic frames communicated in the first protocol are repetitions of one of common or silence symbols at consecutive every other intervals;
• and
• all enhanced frames communicated in the second protocol include a symbol designated as an inserted symbol which is other than a silence symbol and which is inserted in at least one interval corresponding to the location of one of the silent symbols of a basic frame.

A method of communicating over a local area network or LAN which includes a plurality of at least three nodes, the plurality of said nodes including a first group having at least two of said nodes therein and including a second group having at least two of said nodes therein, a communication medium connecting the nodes, interface means associated with the first group of nodes and operative for supplying signals to the medium to establish network operational activity, and interface means associated with the second group of nodes and operative for supplying signals to the medium to establish network operational activity, the first group of nodes includes all of the nodes, the second group of nodes includes less than all of the nodes, each node of the second group is an enhanced node and each node of the first group is a basic node;

• said method comprising:
• communicating information between selected basic nodes by applying predetermined signals at selected regularly occurring intervals from the interface means of the basis nodes in compliance with a first predetermined communication protocol;
• communicating information between selected nodes by applying predetermined signals at selected regularly occurring intervals from the interface means of the enhanced nodes in compliance with one of the first or a second predetermined communication protocol;
• applying signals in predetermined patterns in both protocols to create network operational activity in both protocols while simultaneously communicating information in only a selected one of the first or second protocols;
• and
• differentiating between the first and second protocols by distinguishing the signals which communicate the information in the first and second protocols.