MAMEWorld Forums - Programming - Dumb serial computing question

So I've been looking into old style serial interfaces, like you would find with hardware buses, and I came across something that I don't understand.

I read in some documentation about the Sony LDP1450 (a serially controlled laserdisc player) that, depending on the baud rate, the commands to be sent can vary, impliying that there's a difference in protocol between different speeds (at 9600 bps a command might take one form, but at 4800 it's something entirely different). Call me naive, but I don't understand why that would be the case for any implementation of a serial protocol, as surely it's the same data just sent at different speeds.

Does anyone have any insight as to what could cause an apparent change in a command along these lines? I just can't grasp it and it's bugging me.

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