Receiver Errors

What happens if there are errors in the received bauds?

No Valid Signal If the receiver has no valid received signal for a period of time. The specification says that a receiver device should hold their last setting for up to 1 second, when a valid signal stops being received.
Corrupted Stop Bauds A DMX receiver can detect corruption of a start or stop baud when the UART sees a byte with an invalid stop baud (i.e., not set to mark). DMX suggests that any receiver that detects an error in the stop baud of any slot within a frame then discards the entire DMX frame. This would protect the receiver from missing reception of a slot, causing the later received slots in a frame to be mis-aligned with their slot position in the sent frame.

The DMX frame has no checksum or error correction. Errors might occur, as bit inversions in the slot data, this would not be noticeable at the receiver.In this form it can only be used for non-critical systems. For volatile (changing) lighting data a small level of corruption might be OK. For example, a receiver that has been receiving a specific slot with a value of 0 for the last few seconds, and then sees a frame with the slot having a value of 128 - perhaps as a result of corruption of a data bit. The receiver adjusts the output. However, the device using the output might not have time to make a change in the brightness before the value is noticeable. The next frame, restore the correct value of the output.

For applications that require an integrity check - or to validate the performance of a DMX bus, the sender can add a System Information Packet (SIP) packet sent after a DMX Frame that provides a CRC over the data in the previous frame.