US 5,513,175 A · Multiplex transmission apparatus

Abstract

A multiplex transmission apparatus includes a communication control circuit, which monitors data output from an output port and which changes the state of the output port to a predetermined specific state when at least part of the monitored data fails to show a predetermined periodic change with respect to corresponding data previously output, and is operated by a power supply voltage applied thereto from a power circuit to carry out data communications with other multiplex transmission apparatuses. A communication IC maintains the operating state of or resets the output port and the communication control circuit of the multiplex transmission apparatus in accordance with the result of detection by a low-voltage detecting circuit, and a gate circuit inhibits the output port from being changed to the specific state by a timer IC when low voltage is detected or during sleep mode.

Claims6

Dependent claims

A multiplex transmission apparatus connected to a second multiplex transmission apparatus by a common transmission line to carry out data communications with the second multiplex transmission apparatus, comprising:

power supply means for applying a power supply voltage to individual parts in the multiplex transmission apparatus;
communication control means for controlling reception of frames which are successively transmitted thereto from the second multiplex transmission apparatus and in which at least part of predetermined data shows a predetermined periodic change, and for outputting the predetermined data in received frames to an output port;
state setting means for detecting the power supply voltage, and for setting states of the output port and said communication control means individually to an initial state in accordance with a detection result;
state control means for monitoring at least part of the predetermined data output from the output port, and changing the state of the output port to a predetermined specific state when said at least part of the predetermined data being monitored does not show a predetermined change with respect to corresponding data previously output;
and
inhibiting means for inhibiting said state control means from changing the state of the output port, in accordance with the detection result derived from said state setting means.

3 more elements

power supply means for applying a power supply voltage to individual parts in the multiplex transmission apparatus;
communication control means for controlling reception of frames which are successively transmitted thereto from the second multiplex transmission apparatus and in which at least part of predetermined data shows a predetermined periodic change, and for outputting the predetermined data in received frames to an output port;
first state setting means for detecting a first voltage level of the power supply voltage, and for maintaining an operating state of the output port while changing a state of said communication control means to an initial state in accordance with a detection result;
second state setting means for detecting a second voltage level of the power supply voltage, and for setting states of both the output port and said communication control means to respective initial states in accordance with a detection result;
state control means for monitoring at least part of the predetermined data output from the output port, and changing the state of the output port to a predetermined specific state when said at least part of the predetermined data being monitored does not show a predetermined change with respect to corresponding data previously output;
and
inhibiting means for inhibiting said state control means from changing the state of the output port, in accordance with the detection result derived from said first state setting means.

4 more elements

Dependencies are inferred from the claim text.

Multiplex transmission apparatus

Life of this patent

Multiplex transmission apparatus

Life of this patent

Abstract

Claims6