Learned about Behringer CT100 Cable Tester – it can test different types of cables and see if they are working or not. Moreover it can generated different types of audio signals including a 1k signal or a 4k signal and you could check for the levels in your audio mixer ( Instead of saying ‘Mic check’ ( Another alternative device, which does the same job was PylePro 12 Plug Pro PCT40 , although I need to know more about it )
Came across a very informational video about sound mixing ( see below ) Learned that, passive DI uses a transformer and both ( active vs passive ) have it own set of advantages and disadvantages. An example for a passive DI box ( availabe in bajao ) would be MILLENIUM POCKET DI 1
https://www.youtube.com/watch?v=l4famaQmWnA