摘要 |
The invention relates to a method and a device for testing and supervising majority votes in a multiplane digital time selector with essentially identical equipment in each of at least three planes (A,B,C) working in parallel. An incoming data flow is distributed to the planes and is allowed to pass through the equipment in each of them and gives rise to outgoing data streams. These outgoing data streams are compared to each other and a majority voted outgoing data flow based upon the comparison is delivered from the unit. An error is periodically introduced in accordance with a predetermined pattern in the three planes and the data streams arriving at the majority vote and the majority voted data flow are compared. If an error is then found in any of the data streams an alarm is emitted. If an alarm (LARM1) is expected that has been caused by an error introduced in accordance with the predetermined pattern, this alarm is identified based upon knowledge of the predetermined pattern in order to distinguish from alarms, which result from errors not introduced in accordance with the pattern.
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