A 0-3 decimal number indicating which S-Link port the signal came in on.
A binary string consisting of any number of bits.
Since no S-Link equipment (that we know of) uses the bit-mode, there are only two cases in which you will see this response:
|As an echo of a bit mode message you just sent|
|Due to a signal transmission error / collision on the S-Link bus.|
lowlevel:slb2 is and echo from a command you just sent to shuffle CD Player #2 on SL2