Option bus

A base digital telephone, comprising:

• an interface to a telephony communications switch;
• option processor means, coupled to the switch, for distributing messages to option modules, said option modules operating to implement one or more functions related to the operation of said base digital telephone, said functions being designated herein as options;
• base processor means, coupled to the switch, for controlling the base digital telephone;
• a plurality of ports for coupling the base processor means and the option processor means via an internal bus to one or more of the option modules;
• wherein, the option processor means comprises:
• means for determining a priority for each of the options;
• means for receiving a message from the switch;
• and,
• means for relaying the message to each of the option modules in priority order and wherein each of the option modules comprises:
• means for recognizing the message as being pertinent to a feature which the respective option module controls;
• means for operating the feature in response to the message and means for modifying the message so as to generate a modified message;
• and,
• means for relaying the modified message back to the option processor.

A plug-in option device system for use with a base digital telephone, said option device system including an option device comprising:

• means for intercepting a message sent by a telephony switch to the base digital telephone;
• means for recognition of the message as being pertinent to a feature which the option device controls;
• means for operating the feature in response to said recognition;
• and,
• means for returning a modified message to the base digital telephone after receiving the message.

A plug-in option device system for using with a base digital telephone, said option device system including an extended keyboard option device comprising:

• means for intercepting an indicator control command;
• means for operating an indicator in response to the indicator control command;
• means for modifying the indicator control command;
• and
• means for returning said modified command to said base digital telephone.

A digital telephone, comprising:

• link interface means for receiving digital data from a telephony line;
• control means, connected to receive the digital data from the link interface means, for generating control messages in response to the digital data;
• audio processing means, coupled to the link interface means, for decoding an audio portion of the digital data and for generating an analog audio signal from said audio portion of the digital data;
• a plurality of ports for receiving auxiliary devices which are referred to as option modules, each of the ports being connected to receive the analog audio signal and at least a portion of the digital data;
• and,
• message passing means, coupled to the control means and each of the ports, for relaying the control messages between the option modules wherein the control messages are routed from the message passing means to a port for an associated option module and back from the port for the associated option module to the message passing means.

In a digital telephone having an interface to a telephony communications switch, an option processor and a base processor coupled to the switch, and a plurality of ports in said telephone connected to said base processor and said option processor via an internal bus for coupling the base processor and the option processor to one or more option modules, said option modules operating to implement one or more functions related to the operation of said telephone, said functions being designated herein as options, a method of communicating between the option modules and the base processor comprising the steps of:

• (a) determining, by the option processor, a priority for each of the option modules;
• (b) receiving, by the option processor, a message from the switch;
• (c) relaying the message from the option processor to a highest priority one of the option modules and from said highest priority one of the option modules back to the option processor;
• (d) continuing to relay the message from the option processor to successive lower priority option modules until a lowest priority option module is reached, and from each said successive lower priority option module back to the option processor, in priority order, wherein:
• upon receipt of a message from the option processor by a receiving option module and prior to relaying said message back to the option processor, said receiving option module is able to recognize said message as being pertinent to a feature which said receiving option module controls, and upon such recognition will operate the feature in response to the message and modify the message so as to generate a modified message;
• and,
• (e) when said message reaches a lowest priority option, relaying the modified message from a lowest priority one of the option modules to the option processor and from said option processor to the base processor.