摘要 |
Data processing equipment suitable for recording details of manually connected telephone calls has a plurality of operator stations with keyboards and VDU's connected in groups to operator's control units which respond to keyed instructions to obtain data from peripheral units storing such data and for recording on magnetic tape cartridge the details of the calls. The magnetic tape cartridge recording units are duplicated and the data to be recorded in the two units, which are separately generated and should be the same, are compared with one another and their validity checked. If both data are valid, whether they differ or not, they are recorded. If only one set of data is valid only the valid data are recorded by both recorders. A marker signal may be recorded to indicate that the data recorded may be incorrect. |