Tony M Sep 6, 2016:

@ Asker (2) There is another point of technical logic here: the apparatus will not work properly if the ports are not connected (at all), or are incorrectly connected (muddled up) — the notion of any interference to the input signals really comes in at a different level, which might allow it to work, but poorly, for example.

Tony M Sep 6, 2016:

@ Asker Do you know what the provenance of this 'English' is? That doesn't sound to me like correct technical EN to me, and I suspect a non-native writer or a previous translation.

I do not believe that 'muddled' could refer to any kind of jamming or interference. I suspect they simply mean that the ports have been 'muddled up' (like « s'emmêler les pinceaux » !) — the wrong ones connected to the wrong ones. The person who plugged them in got them confused... If there were only 2 ports, we might say that had been 'inverted' or 'reversed'; the use of 'muddled' here might suggest there are more than 2 ports, and the writer was at a lost to know how best to express the notion!

Note too that 'muddled' is applied to 'ports' (i.e. a physical connection point) rather than to (e.g.) incoming signals — you can't really 'jam' or 'interfere with' a 'port', only with the signal going into it.