Panasonic JB-3300 Technical Manual page 149

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PARITY ENABLE BLOCK
When a memory device in an expansion unit or other optional
device becomes faulty, the *IOCHCK line becomes active and an
NMI is generated. This operation is enabled as follows:
I/O address: 0061 (HEX)
Command: To enable, set bit 5 to "0".
To disable, set bit 5 to "1".
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